Breech Face Pitting From Gas Cutting Using SPPM In Weak 9mm Loads?

[contactcole]

I have a Gen3 Glock 17 and a former Gen2 Glock 19 I've run lots of (old red box CCI) SPPM though. My current Gen3 Glock 17 has about 7-8k through it (maybe more) and the Gen2 Glock 19 had >20k. About 2/3 of these have been these SPPM because I bought about 30k in FTF deals for $10-$20k back in the crazy price days. And, I've run a few hundred SRP and SRPM as well. Loads have cycled fine with no change in accuracy. And, I do not change my powder charge. I've always known all these 124gr FMJ/Plated SPPM loads are well under-pressure as the bulk have run only 1000-1050fps, or even less for some LRN loads used in the Glock 19 w/ LWD and KKM barrels.

Breech face gas cutting has occured (consistent with the primer cup), and has for some time in this Glock 17, and it was the same in the G19. I've also run these loads in other guns with similar results (e.g. slight breech face marks), though the ring has not formed due to lower volume shooting. I've even run them in once-fired, sorted .45acp brass (with a hammer-fired 1911: Unique 3.9-4.0gr w/ 200gr LSWC @ 1.135", which is a tame load) to rule out over-pressure, flash hole difference, primer impact deformation, stretched primer pocker (e.g. brass issues), etc. (same result). It does not seem to matter if I use a faster or slower powder, with mixed brass or not, nor does it seem to matter using once-fired brass or more-fired. I have not observed damage to primers, fired primers remain seated (i.e. are not loose), and new primers seat fine in fired brass (i.e. smooth, with slight resistance and seat fully) using two different Dillon SD progressives.

So, becoming more curious only recently, I've narrowed my theory of late, and do not think brass is the culprit. I believe the harder primer cup is not expanding to allow a tight primer pocket seal at the lower handgun pressures, 9mm or .45acp. Meaning, not over-pressure or a streched primer pocket, but under-pressure (weak) loads with these harder older red box CCI SPPM primers. I do think higher 9mm pressure (vs. .45acp) exacerbates it, but the 9mm pressure, at least the weak 1000-1050fps loads I've run, is still below the pressures needed to seal these SPPM in the primer pocket, meaning more gas escapes. And, since most of the cutting in my 9mm is from (older red box CCI) SPPM, the hardness of the cup must be more like rifle primers. I've heard/read, and have experienced myself via light primer strikes, that these CCI SPPM are harder than current production and much more like rifle primers. So, none of this may matter if you don't have those, but could be applicable if you plan to run SRP/SRPM (i.e. harder cup primers) in 9mm.

If I push the 9mm faster, to +p or +p+, it may go away or lessen, and I'm testing that now running all loads at ~1150fps. I have already noticed differences in primer flow patterns (see image below). But, I can't push .45acp fast enough if low pressure is the cause. Regarding primer hardness this picture of primers shows differences in indent depth and primer flow into Glock striker hole. As is often the case, the picture is not as clear as real life. These examples are representative of the lot:

Top (blue marker) = Older Red Box CCI SPPM w/ 4.7gr Unique (some primer flow, shallow indent)

Second Row (red marker) = Older Red Box CCI SPPM w/ 4.2gr Unique (little/no primer flow, shallow indent)

Third Row (cleaned/tumbled) = Range Brass (clear primer flow, deeper indent)

Bottom (cleaned/tumbled) = SPP w/ 4.2gr Unique (clear primer flow, deeper indent)

(Note: A Berry's 124gr FP w/ 4.9gr Unique @1.030" ran ~1150fps for me and 5.2gr ~1210fps, so the 4.7gr load pictured is below 1150fps.)

Update 2/19/12: I ran the 4.9gr Unique load and primer flow and indent depth appears identical to the 4.7gr load. So, >4.7gr provides enough pressure for primer flow that should seal the pocket. Also, I just swapped 4k SPPM with SPP at the local gun show. The guy will trade my remaining 5k SPPM next show. So, that will be the end of it. If I'd have known SPPM and low pressure loads was the cause sooner I'd had swapped them already.

I've pretty much always run weak to mid-level loads. All along, and for many years, I thought the issue was using mixed brass and I did not want to sort. That, and I did not really care since I knew the loads were safe. But, I'm beginning to think conclusively that too weak loads using harder primers is the issue. More rounds downrange with hotter loads will prove or disprove that theory.

I view Glocks as tools, and I consider Glocks "throwaway" guns somewhat anyway. I consider this cosmentic for now, and will monitor to see if breech integrity could become compromised if ring gets deeper. Obviously, this does not matter to me in this Glock 17 (and did not matter in my former Glock 19) as I keep running SPPM, even SRP and SRPM. But, I don't use SPPM, SRP or SRPM in any volume in my other 9mms due to this, nor would I run them in any 9mm I really cared about, and stick with using SPP instead for now. Even if the issue goes away, it may be just these older red box CCI primers, but I won't know that for sure as I've not run other SPPM in high volume. Regardless, I often share SPPM, even SRP and SRPM run fine in 9mm. And, they do. I figured I'd share this as a PSA to let folks know your breech may show accelated wear using SPPM, SRP or SRPM if you run weak loads. To me, though I'll bump up the load to see if it goes away, it's worth it given what I paid for these primers and how cheap Glocks are since I've saved more than enough to buy the gun again.

Edited February 20, 2012 by contactcole

[Youngeyes]

I don't know if this is the same thing, but I had the same problems with a 44 mag. The culprit was the RP brass. It's got a champher and didn't allow a full seal. The primer was not fully supported. I had a friend slightly redrill and true the flash hole and problem solved. The primer sat a little deeper and no blow back causing breechface cutting. If you look at your pictures you can see the difference in the the way the primer is held by the RP VS Speer. YMMV

Edited February 19, 2012 by Youngeyes

[GrumpyOne]

It's not a theory about the primers being too hard. It's a fact, and a well known one. If you are shooting very weak loads, you need a much softer primer (Federal is the softest). The primers should be flat after being fired, not with round edges as seen in your pics. Most use SPM's or SRP's to keep from having primer flow in hot rounds, not for their extra oomph in igniting powder.

[DyNo!]

I wouldn't say it is well known.

I have observed a similar thing happening and during the primer shortage, you'd find a number of people who recommended small pistol magnum primers for minor 130PF 9mm loads. I even used an established load that wasn't too wimpy - 4.1 grains of Titegroup under a 124gr bullet.

DO NOT DO IT.

I changed all of my components and one slide later, all blame could be assigned to SPM primers. Even hard Wolf SP primers didn't contribute to erosion. Don't shoot SPM in minor, it isn't worth finding out whether your slide will survive it or not:

http://www.brianenos.com/forums/index.php?showtopic=123968&st=0&p=1401215&hl=erosion&fromsearch=1entry1401215

http://www.brianenos.com/forums/index.php?showtopic=125405&st=0&p=1421046&hl=erosion&fromsearch=1entry1421046

http://www.brianenos.com/forums/index.php?showtopic=138496&st=0&p=1558305&hl=erosion&fromsearch=1entry1558305

http://www.brianenos.com/forums/index.php?showtopic=141371&st=0&p=1591530&hl=erosion&fromsearch=1entry1591530

http://www.brianenos.com/forums/index.php?showtopic=117267&st=0&p=1419985&hl=erosion&fromsearch=1entry1419985

http://www.brianenos.com/forums/index.php?showtopic=101751&st=0&p=1160502&hl=breechface%20erosion&fromsearch=1entry1160502

http://www.brianenos.com/forums/index.php?showtopic=67126&st=0&p=778701&hl=breechface%20erosion&fromsearch=1entry778701

Edited February 19, 2012 by DyNo!

[contactcole]

It's not a theory about the primers being too hard. It's a fact, and a well known one. If you are shooting very weak loads, you need a much softer primer (Federal is the softest). The primers should be flat after being fired, not with round edges as seen in your pics. Most use SPM's or SRP's to keep from having primer flow in hot rounds, not for their extra oomph in igniting powder.

I can tell you SPPM gas cutting in low pressure 9mm loads is not "well known" in many circles definatively. SRP and SRPM, maybe, but not SPPM. I've heard/had many suggested causes, including from many long-time reloaders (heck, I'm 15+ years myself), that the cause was bad primers, stretched brass pocket, bad brass, over-pressure, hard primers, user error, fast powder, and more. I eliminated all the other possibilities and was left with only too hard primers in too low pressure loads. To have the definative cause be too hard SPPM primers in too weak loads was news to me, and will be to many. Now, I know.

I wouldn't say it is well known.

I have observed a similar thing happening and during the primer shortage, you'd find a number of people who recommended small pistol magnum primers for minor 130PF 9mm loads. I even used an established load that wasn't too wimpy - 4.1 grains of Titegroup under a 124gr bullet.

DO NOT DO IT.

I changed all of my components and one slide later, all blame could be assigned to SPM primers. Even hard Wolf SP primers didn't contribute to erosion. Don't shoot SPM in minor, it isn't worth finding out whether your slide will survive it or not:

http://www.brianenos.com/forums/index.php?showtopic=123968&st=0&p=1401215&hl=erosion&fromsearch=1entry1401215

http://www.brianenos.com/forums/index.php?showtopic=125405&st=0&p=1421046&hl=erosion&fromsearch=1entry1421046

http://www.brianenos.com/forums/index.php?showtopic=138496&st=0&p=1558305&hl=erosion&fromsearch=1entry1558305

http://www.brianenos.com/forums/index.php?showtopic=141371&st=0&p=1591530&hl=erosion&fromsearch=1entry1591530

http://www.brianenos.com/forums/index.php?showtopic=117267&st=0&p=1419985&hl=erosion&fromsearch=1entry1419985

http://www.brianenos.com/forums/index.php?showtopic=101751&st=0&p=1160502&hl=breechface%20erosion&fromsearch=1entry1160502

http://www.brianenos.com/forums/index.php?showtopic=67126&st=0&p=778701&hl=breechface%20erosion&fromsearch=1entry778701

I agree it's not "well known" that SPPM can gas cut in too low pressure loads. Very helpful links. Thanks. One load I ran in volume was a 124gr FMJ 3.9-4.0gr TG load.

Update: I ran the 4.9gr Unique load today and primer flow and indent depth appears identical to the 4.7gr load. So, >4.7gr provides enough pressure for primer flow that should seal the pocket. Also, I just swapped 4k SPPM with SPP at the local gun show. The guy will trade my remaining 5k SPPM next show. So, that will be the end of it. If I'd have known SPPM and low pressure loads was the cause sooner I'd had swapped them already.

Edited February 20, 2012 by contactcole

[10mmdave]

Interesting thread, had the same thing happen with Fed SPM bought during the shortage.

The erosion done to the revo was with 170 PF loads, the slide was 125-130 PF loads.

The revo loads were all Clays, the auto 90% Bullseye with some other powders mixed in.

Edited February 20, 2012 by 10mmdave

[contactcole]

Final Update: I ran matching loads in CCI SPP and CCI SPPM. The SPPM are harder. My testing puts this to bed for me and conclusively proves that harder SPPM, SRP and SRPM can cause breech cutting around the primer cup using weak loads because the primer does not deform to seal the primer pocket. Picture of SPPM vs. SPP:

These two cases are representative of loads fired. I've since traded all my SPPM for SPP. The SPP indent and primer flow is more pronounced, and it's much more noticeable in real life.

Edited March 18, 2012 by contactcole

[njl]

It'll be interesting to see what Glock says when you send them that slide. I bet if you wait until it fails, they'll replace it.

[DyNo!]

Can we get a tack?

The reason many of us used SP Mag primers was because of the shortage.

We will likely be headed into another shortage during this election cycle and keeping this thread visible will make this problem well known and completely avoidable.

[Nuke8401]

Dang, I just loaded 1000 147 JHP Zero's with TG, chrono about 900-925 with Remington SPM primers.

At 132 - 136 PF this is on the medium/hot side for minor.

Any opinions if 1000 rounds of this will damage a G34?

Not looking forward to pulling 1000 rounds.

David E.

[contactcole]

Dang, I just loaded 1000 147 JHP Zero's with TG, chrono about 900-925 with Remington SPM primers.

At 132 - 136 PF this is on the medium/hot side for minor.

Any opinions if 1000 rounds of this will damage a G34?

Not looking forward to pulling 1000 rounds.

David E.

Not sure, but you should be okay as that is not a real weak load like I ran. Also, yours are Rem SPPM and mine were CCI.

I can tell you the loads that gas cut for me where using older red box CCI SPPM running under 130pf, many well under. As noted above, primer flow (i.e. deformation that will seal the primer pocket) exists running about 140pf, and I'm running everything at least that now with the last bit of CCI SPPM I have. I can't speak from experience for loads around 135pf w/ CCI SPPM because I did not run them in the test process noted here.

Edited March 19, 2012 by contactcole

[DyNo!]

4.0 of Titegroup behind a 124gr bullet was enough to show erosion in my experience with Federal SPM primers.

I'd pull them.

[jmorris]

It'll be interesting to see what Glock says when you send them that slide. I bet if you wait until it fails, they'll replace it.

They will say "Didn't you read your manual, where it said "no reloads"."

There are a lot of things not "well known" or ignored. At least this one didn't hurt you.

[GrumpyOne]

Ok, I just took my Shadow apart and cleaned the breech face to check for erosion. First, I have shot nothing but my minor loads out of this gun, all loaded with Win SPM primers. The loads were 4.2 of 320 with a MG 124 JHP at 1.085 (approximately 750 rounds), and 3.8 of 320 with a PD 147 FMJ (approximately 500 rounds) at 1.145. The primers are flat after shooting, apparently sealing well, as there is absolutely no evidence of pitting, erosion, or anything else. I took a sewing needle and dragged/scraped it across the breech face and felt nothing except for where the needle slid into the FP hole. There is only the slightest discoloration where the primer would strike the breech face when fired, but can only be seen in the correct light and angle. I will check periodically to see if anything changes.

Thoughts?

Btw, CCI primers are considered harder than most.

[contactcole]

Dang, I just loaded 1000 147 JHP Zero's with TG, chrono about 900-925 with Remington SPM primers.

At 132 - 136 PF this is on the medium/hot side for minor.

Any opinions if 1000 rounds of this will damage a G34?

Not looking forward to pulling 1000 rounds.

David E.

4.0 of Titegroup behind a 124gr bullet was enough to show erosion in my experience with Federal SPM primers.

I'd pull them.

Loads near and under 130pf w/ CCI SPPM resulted in gas cutting for me. And, as show in the photos, the low pressure rounds show very little if any primer flow. However, it's a bit easier to see primer flow in a Glock because of the large striker opening. The 4.7gr Unique noted above resulted in clear primer flow, but I'm running 4.9gr (~1150fps) for a bit added insurance with the last CCI SPPM I have. The question I have is whether the 147gr @ 925fps (~136pf) loads show enough primer flow. If not, it could be an issue. If so, he should be okay. But, I don't have experience with Rem or Fed SPPM.

Ok, I just took my Shadow apart and cleaned the breech face to check for erosion. First, I have shot nothing but my minor loads out of this gun, all loaded with Win SPM primers. The loads were 4.2 of 320 with a MG 124 JHP at 1.085 (approximately 750 rounds), and 3.8 of 320 with a PD 147 FMJ (approximately 500 rounds) at 1.145. The primers are flat after shooting, apparently sealing well, as there is absolutely no evidence of pitting, erosion, or anything else. I took a sewing needle and dragged/scraped it across the breech face and felt nothing except for where the needle slid into the FP hole. There is only the slightest discoloration where the primer would strike the breech face when fired, but can only be seen in the correct light and angle. I will check periodically to see if anything changes.

Thoughts?

Btw, CCI primers are considered harder than most.

What's the velocity on those? If you are getting primer deformation pressure is likely high enough to deform the primer enough to completely seal the pocket.

Loads I ran in high volume w/ CCI SPPM (that gas cut) were ~1000-1050fps w/ 124gr FMJ/Plated resulting in a 130pf or under. These were weak loads. My SPPM loads in this test were ~1150fps (>140pf) and have not show issues, but I can't run these in high volume with CCI SPPM to be certain because I traded my remaining 9k for SPP.

CCI are harder. That's been my experience as well. These CCI SPPM are the only primers I've ever had repeated light primer strikes with in Glocks.

Edited March 20, 2012 by contactcole

[CocoBolo]

Just my .02, I'm with GrumpyOne shot lots of SPM (Win, MagTech, CCI) many thousands, at minor in one of my open guns and my CZ Shadow, no issues with cutting the breach face and no primer flow...

The case here should be correctly stated: Low Velocity 9 mm load with slow powder (unique), and Federal SPM primers. I think most of us get different results due to using different brand of primers with a faster powder.

Try loading with WST, fast, cheap, clean. DIY gave TiteGroup the death blow since it eats the breach face, well if you shoot enough it melts the grips off as well.

[contactcole]

Just my .02, I'm with GrumpyOne shot lots of SPM (Win, MagTech, CCI) many thousands, at minor in one of my open guns and my CZ Shadow, no issues with cutting the breach face and no primer flow...

The case here should be correctly stated: Low Velocity 9 mm load with slow powder (unique), and Federal SPM primers. I think most of us get different results due to using different brand of primers with a faster powder.

Try loading with WST, fast, cheap, clean. DIY gave TiteGroup the death blow since it eats the breach face, well if you shoot enough it melts the grips off as well.

As noted, my experience relates only to ~20k of CCI SPPM w/ Unique and Titegroup in 9mm using mixed brass and >1k w/ Bullseye w/ .45acp using Blazer small primer brass. As noted, powder burn rate did not matter. My opinion based on my experience is that it's due to too low pressure (>130pf, and well under at that) in 9mm and too low pressure in .45acp regardless. I only run SPP now, but would likely be fine runnning SPPM >140fp in 9mm if that's all I had.

p.s. I will not run .45acp in SPPM again because I don't think the pressure can safely get high enough to cause primer flow that will reliably seal the primer pocket.

Edited March 24, 2012 by contactcole

[GrumpyOne]

Dang, I just loaded 1000 147 JHP Zero's with TG, chrono about 900-925 with Remington SPM primers.

At 132 - 136 PF this is on the medium/hot side for minor.

Any opinions if 1000 rounds of this will damage a G34?

Not looking forward to pulling 1000 rounds.

David E.

4.0 of Titegroup behind a 124gr bullet was enough to show erosion in my experience with Federal SPM primers.

I'd pull them.

Loads near and under 130pf w/ CCI SPPM resulted in gas cutting for me. And, as show in the photos, the low pressure rounds show very little if any primer flow. However, it's a bit easier to see primer flow in a Glock because of the large striker opening. The 4.7gr Unique noted above resulted in clear primer flow, but I'm running 4.9gr (~1150fps) for a bit added insurance with the last CCI SPPM I have. The question I have is whether the 147gr @ 925fps (~136pf) loads show enough primer flow. If not, it could be an issue. If so, he should be okay. But, I don't have experience with Rem or Fed SPPM.

Ok, I just took my Shadow apart and cleaned the breech face to check for erosion. First, I have shot nothing but my minor loads out of this gun, all loaded with Win SPM primers. The loads were 4.2 of 320 with a MG 124 JHP at 1.085 (approximately 750 rounds), and 3.8 of 320 with a PD 147 FMJ (approximately 500 rounds) at 1.145. The primers are flat after shooting, apparently sealing well, as there is absolutely no evidence of pitting, erosion, or anything else. I took a sewing needle and dragged/scraped it across the breech face and felt nothing except for where the needle slid into the FP hole. There is only the slightest discoloration where the primer would strike the breech face when fired, but can only be seen in the correct light and angle. I will check periodically to see if anything changes.

Thoughts?

Btw, CCI primers are considered harder than most.

What's the velocity on those? If you are getting primer deformation pressure is likely high enough to deform the primer enough to completely seal the pocket.

Average FPS is 945, for a PF of around 138. Going lower with the charge makes the gun feel sluggish....

Loads I ran in high volume w/ CCI SPPM (that gas cut) were ~1000-1050fps w/ 124gr FMJ/Plated resulting in a 130pf or under. These were weak loads. My SPPM loads in this test were ~1150fps (>140pf) and have not show issues, but I can't run these in high volume with CCI SPPM to be certain because I traded my remaining 9k for SPP.

CCI are harder. That's been my experience as well. These CCI SPPM are the only primers I've ever had repeated light primer strikes with in Glocks.

It has been said that the WSPM primers are the same cup as the WSPP...That being said, if the SPP will seal the cup, then the SPMP will seal as well. There was a thread on primers on here not long ago, and somoeone actually corresponded with several of the primer manufacturers and got the cup hardness of quite a few of the different types. The only difference (IIRC) between the WSPP and the WSPMP was the heat of the flame...

For those that want the linkies... http://www.jamescalhoon.com/primers_and_pressure.php

http://www.sksboards.com/smf/index.php?topic=56422.0

PRIMER CHART & REFERENCE GUIDE

Small Handgun Standard .017" cup thickness

CCI 500

Federal 100 - Has a soft cup - good to use if hammer strike is light.

Federal 100M - Match version of above

Magtech PR-SP

Magtech PR-SPC - Lead-free "Clean Range" primer for indoor ranges etc.

Remington 1 ½

RWS 4031

Winchester WSP

Wolf Small Pistol SP - brass cup

Small Handgun Magnum .017" cup thickness

CCI 550 See Note 1 at the bottom of page

Federal 200

Federal 200M - Match version of above

Magtech PR-SPM

Remington 5 ½

RWS 4047

Winchester WSPM

Wolf Small Pistol Magnum SPM - brass cup

Large Handgun Standard .020" cup thickness

CCI 300

Federal 150 - Has a thinner cup

Magtech PR-LP

Remington 2 ½

RWS 5337

Winchester WLP

Wolf Large Pistol LP - brass cup

Large Handgun Magnum .020" cup thickness

CCI 350

Federal 155

Wolf Large Pistol Magnum LPM - brass cup

Small Rifle Standard

CCI 400 -thin .020" cup, not recommended for AR15 use by CCI/Speer. Good for .22 Hornet, .30 Carbine. See Note 1 at the bottom of the page

CCI BR4 - match primer with a thicker .025" cup.

Federal 205 - Mil-Spec cup thickness according to Federal - okay for 5.56mm. .0225" cup thickness.

Federal 205M - same as the 205 but the match version.

Magtech PR-SR - .025" cup thickness (not much feedback yet on this new primer as to AR15 suitability but with the same cup thickness as the Rem 7 1/2 it looks good so far)

Remington 6 ½ - thin .020" cup, intended for older, lower pressure rounds Remington says do not use for the .223 Rem or other similar pressure rounds. Good for .22 Hornet, .30 Carbine.

Remington 7 ½ BR - A match or "bench rest" primer. Lyman & Nosler classify this primer as a Standard. Remington says the compound is the same as the 6 1/2 but with a thicker .025" cup.

RWS 4033

Winchester WSR - some piercing issues noted when changed from silver to brass cup. Cup thickness is a bit thinner at .021". Most say they are good to go for the AR15 despite that, probably because of the hardness of the cup. Some feel they are less resistant to higher pressures.

Wolf Small Rifle SR - soft, sensitive copper cup, not recommended for AR15/military rifle use or high pressure rounds.

Small Rifle Magnum

CCI 450 - same thicker .025" cup as the BR4 and #41.

CCI #41 - commercial version of the fully-qualified DOD primer for use in U.S. military ammo. With this primer there is more 'distance' between the tip of the anvil and the bottom of the cup than with other CCI SR primers. .025" thick cup. Same primer mix as CCI 450.

Remington 7 ½ BR - A match or "bench rest" primer. Hornady, Handloads.com, and Chuck Hawks classify this primer as a Magnum, differing from other sources that classify it as a Standard. .025" cup thickness.

Wolf Small Rifle Magnum SRM - hard, less sensitive brass cup intended for AR15/military rifle and high pressure rounds.

Wolf Small Rifle 223 SR223 - "This is the newest primer available in the Wolf line. It is ever so slightly hotter than the small rifle magnum primer and it comes with a brass colored thick cup. This primer can be used in place of the SRM primer or used when a different powder is used that is hard to ignite."

Large Rifle Standard

CCI 200 - mild in brisance. Hard enough for use in semi-automatics.

CCI BR2 - same as the 200 but the match version. Hard enough for use in semi-automatics.

Federal 210 - medium brisance between CCI/Remington & Winchester. Do not use in semi-automatics.

Federal 210M - match version of the above primer. Do not use in semi-automatics.

Magtech PR-LR

Remington 9 ½ - mild in brisance.

RWS 5341

Winchester WLR - the hottest standard primer. Hard enough for use in semi-automatics.

Wolf Large Rifle LR - all brass - Used by noted match shooter David Tubbs who says: "Be sure they are seated into the case - if not they can be hard to ignite. Russian primers use a different sinoxide compound (closer to the European type), which, in my testing, consistently delivers better extreme spreads over Federal..." Hard enough for use in semi-automatics.

Large Rifle Magnum

CCI 250

CCI #34 - commercial version of the fully-qualified DOD primer for use in U.S. military ammo.

Federal 215 - original magnum primer

Remington 9 ½ M - mildest magnum primer.

RWS 5333

Winchester WLRM

Wolf Large Rifle Magnum LRM - all brass

50 BMG

CCI #35 - commercial version of the fully-qualified DOD primer for use in U.S. military ammo.

Winchester 8312

Primers recommended for use in .223 Rem/5.56 semiautomatic rifle loads:

CCI #41, 450, BR4 (#41 & 450 good with ball powder)

Federal 205, 205M

Remington 7 1/2 BR (good with ball powder)

Winchester WSR (good with ball powder)

Wolf SRM (good with ball powder)

Wolf SR223 (hotter than SRM - great with ball powder)

Primers recommended for use in .308 Win/7.62x51/7.62x39 semiautomatic rifle loads:

CCI #34, 200, BR2, CCI 250

Winchester WLR, WLRM (good with ball powder)

Wolf LR

##################################################################################

NOTE 1: According to Speer/CCI Technical Services - Both the CCI 550 Small Pistol Magnum and CCI 400 Small Rifle primers are identical in size. Both primers use the same cup metal and share the same cup thickness. Both primers use the same primer compound formula and same amount of primer compound. They can be used interchangeably.

Edited March 24, 2012 by GrumpyOne

[GrumpyOne]

Compare the 357 SIG round to the 357 Magnum round. The SIG comes from the factory with SPP, while the magnum comes from the factory with a SPMP. So, you would think the 357 magnum has a higher pressure range, right? Wrong. The SIG has a higher pressure....much higher... The 357 SIG is rated at 40,000 PSI, but still a regular small pistol primer. It's 5,000 PSI higher than the magnum, yet the manufacturers see no reason to build it with a magnum primer......Maybe not because of the pressure, but because of less powder to ignite.....The magnum primers are not "harder"...They are "hotter", to ignite larger volumes of powder, in longer cases. Cup thickness and hardness are the same, for just about all manufacturers, between magnum and regular pistol primers. Some might be harder (CCI, Wolf, Tula), but most are the same.

I submit, that if you are experiencing "breech face erosion", that it might not be your primer at fault. It very well may be your brass. There's a good reason Major 9 shooters leave their brass after a few reloadings.

[contactcole]

Compare the 357 SIG round to the 357 Magnum round. The SIG comes from the factory with SPP, while the magnum comes from the factory with a SPMP. So, you would think the 357 magnum has a higher pressure range, right? Wrong. The SIG has a higher pressure....much higher... The 357 SIG is rated at 40,000 PSI, but still a regular small pistol primer. It's 5,000 PSI higher than the magnum, yet the manufacturers see no reason to build it with a magnum primer......Maybe not because of the pressure, but because of less powder to ignite.....The magnum primers are not "harder"...They are "hotter", to ignite larger volumes of powder, in longer cases. Cup thickness and hardness are the same, for just about all manufacturers, between magnum and regular pistol primers. Some might be harder (CCI, Wolf, Tula), but most are the same.

I submit, that if you are experiencing "breech face erosion", that it might not be your primer at fault. It very well may be your brass. There's a good reason Major 9 shooters leave their brass after a few reloadings.

All suspect CCI SPPM 9mm loads were <130pf, many ~125pf. Almost all 9mm brass was once fired (i.e. reloaded for the first time). I have >30k of 9mm brass and a system to cycle it. Regardless, I can't see 125-130pf 9mm loads wearing out brass after one loading. And, the .45acp small primer brass was once fired for sure. Can't get much better than that for non-new reloading brass. I'm sticking to my belief of too low pressure not deforming the harder CCI SPPM primer enough to seal the pocket. The data supports that. I changed nothing in my test of SPPM other than increasing to >140pf and the gas cutting stopped. And, I think the SPPM gas cutting in the much lower pressure .45acp lends added support to my too low pressure theory. YMMV, but I have my answer.

p.s. As a reminder, my 30k of CCI SPPM were the older red box variety. New CCI SPPM, and other brand SPPM, may vary.

Edited March 26, 2012 by contactcole

[DyNo!]

After I went to Federal Small Pistol Primers, my problems went away.

I kept the same load and the same brass.

[GrumpyOne]

By the data I posted above, the CCI SPMP are the same cup thickness and hardness of the CCI SRP. If that was what you were using, that also would lead me to believe that the breech face cutting was caused by the primer not sealing. But, the data only says that the CCI's were harder. I suspect that the regular variety of SPMP's are just the same hardness as the SPP and can be used without damage to the breech face.

While CCI may make their primers a bit harder for the magnum primers, it appears that other manufacturers do not. I can't see most manufacturers making a thicker/harder cup for magnum primers, as it's just not economical when the cup from a regular SPP will do just fine...CCI may be different in that respect though.

[trickpony]

My new S&W M&P 9Pro is experiencing the same problem, the breech face is eroding after less than 2000 rounds of mainly factory PMC ammo. I've shot a handful of reloads in it but don't think I should be seeing this on such a new gun... What to do??

[twodownzero]

Use a faster powder. Higher peak pressures == a better seal.

[trickpony]

Use a faster powder. Higher peak pressures == a better seal.

I can barely keep up with 40 and 223 loading, I didn't want to start loading 9mm too

I've got a bunch of titegroup and N320 around so guess that's a start.