Should a 135pf load flatten Federal SP Primers?

[DWFAN]

Just got done chrono'ing some loads. My first time working with Titegroup and Im kind of baffled that 4.1grs under a 124 MG JHP would flatten (Federal small pistol) primers? They were only chronoing 1074-1106 and some of the primers were pretty flat.

Is this normal ? Should I be concerned?

4.0 grs showed some flattening, and 4.2 a little more than 4.1, but since 4.1 made 133pf and up, thats what I would like to go with.

Top middle, right side 3rd down are some of the worst, but some of the others look worse in person. Hopefully someone can tell me if this is ok.

Edited March 11, 2010 by DWFAN

[PCC-1]

Whats your OAL... might be a little short and building up some unneeded pressure. I would be concerned. It does happen, but its not normal.

[DWFAN]

OAL 1.14, not exactly short. 95% sure im not getting set back either.

If I was building high pressure, would my FPS be higher ? Im pretty much inline with the book range of powder charge and FPS.

Edited March 11, 2010 by DWFAN

[Sarge]

At face value the ones you mentioned appear to look like overpressure. But then again Federals are soft. I have loaded alot of 124 MG's over 4.3 TG at 1.14 but never with a federal SPP. No signs of pressure for me with other primers.

[PCC-1]

OAL 1.14, not exactly short. 95% sure im not getting set back either.

If I was building high pressure, would my FPS be higher ? Im pretty much inline with the book range of powder charge and FPS.

OAL should be OK at 1.14.. Your FPS would not necessarily be higher, as the pressure can spike and dissipate before the bullet gets up to full speed and out the end of the barrel. Not sure what is happening though.

I once had a charge block that was acting screwy and every 6th or 7th round threw an extra few tenths grains in to the case.... It was causing the same thing... flat primers only every so often... not all the time... i finally figured it out by chrono shooting one at a time and inspecting the case and primer one at a time before i shot the next one. With mine though i did have the increase in FPS.... Good luck with figuring it out...

[Flexmoney]

My Federals don't flatten and I run 4.2g of TG with a similar Zero bullet at about the same OAL.

I'd look toward setback, barrel leading, or bullet contact with the rifling (got an aftermarket barrel?)

[DWFAN]

Ok. Lets revisit set back. I went and loaded some more. It seems I can push the bullet into the case. I tried more crimp, less crimp, no Lee FCD, with FCD. The only pattern I've found is the GFL(i) and R-P brass I cannot push back in, but FC, PMC and Blazer I can.

Im loading on a Lock 'n Load AP. Hornady 9mm dies and a Lee FCD.

Anyone got any ideas on what to try now?

[Sarge]

Crimp should only be enough to remove the bell. The bullet tension comes primarily from the initial sizing of the case but too much crimp can loosen things up. I have only had one round ever set back on me. I found it by checking before shooting it thank goodness. It was LY brass and the bullet was nowhere near tight. I measured the case walls and it was way too thin and was not able to size down at all. But I have had great results with all the brass you mentioned. Sounds like somehow your brass is not resizing properly? Is the die all the way down and tight?

Did you MIC the bullets? There have been bad batches in the past if I recall. Not many, but it is possible.

[SLM]

And is your sizing die set properly? Screwed down far enough? Run some brass through the press and make sure the brass is being sized properly. Right after the brass comes out of the sizing die you shouldn't be able to push a bullet in by hand. The outside diameter of the brass and bullet should be about the same, IE the inside diameter of the case should be smaller than the outside diameter of the bullet. Make sure your expanding/flaring die isn't adjusted too far down. With jacketed bullets I don't even use an expand / flare die. I want all the neck tension I can get.

[DWFAN]

Yup, you guys got it. The sizing die wasnt down all the way. Never a problem with all the lead I was shooting. I wasnt using an expander, and I couldnt put a bullet in by hand, but I guess the very small amount the sizer needed to be screwed down was enough to not hold the bullet.

I feel kinda dumb, but I guess it happens. Thanks for the replies and help.

[SLM]

Yup, you guys got it. The sizing die wasnt down all the way. Never a problem with all the lead I was shooting. I wasnt using an expander, and I couldnt put a bullet in by hand, but I guess the very small amount the sizer needed to be screwed down was enough to not hold the bullet.

I feel kinda dumb, but I guess it happens. Thanks for the replies and help.

Glad you got it sorted out. The lead bullets are most likely .001" or so bigger than the jacketed so the problem didn't manifest itself until you went to a "smaller" bullet.

[LPatterson]

Yup, you guys got it. The sizing die wasnt down all the way. Never a problem with all the lead I was shooting. I wasnt using an expander, and I couldnt put a bullet in by hand, but I guess the very small amount the sizer needed to be screwed down was enough to not hold the bullet.

I feel kinda dumb, but I guess it happens. Thanks for the replies and help.

Earlier you stated that part of your brass was working without the die fully screwed down, so have you reexamined these brands to make sure they work with the new die setting? My OCD is too bad to allow me to use mixed brands but it would seem to me that thin brass and thick brass are not going to grip the bullet the same causing differences in pressure and velocity. I know the economy is bad and we want to save every penny we can but it doesn't make sense to me to use pickup brass to save money if it makes inaccurate ammo. Also you said you had 3 brands where you could push the bullet in by hand so do you want to keep using them and risk setback because a speed mag dump is not the way to end a practice session. The gun survived but the shorts didn't.

[DWFAN]

Yes, I loaded some of the culprits (FC, PMC, Blazer) and the (REM, GFL that worked before) after I fixed the sizing die and they all hold perfectly now. My fingers and thumb are sore from checking about 400 rounds last night.

I agree, speed mag dumps are probably no fun. Thats why I have about 200 rounds to pull, resize and reload. As I work through these next few hundred, I'll for sure be checking for this issue before I load so many.

[G-ManBart]

Your FPS would not necessarily be higher, as the pressure can spike and dissipate before the bullet gets up to full speed and out the end of the barrel.

Where in the world are you getting that from?

The pressure is almost always at it's peak well before the bullet is up to full speed, or out of the barrel...heck, it may not even be out of the case when the pressure peaks (spikes).

[Sarge]

I feel kinda dumb, but I guess it happens. Thanks for the replies and help.

No need to feel dumb about it. Dumb would be not taking advantage of all the helpful members here. Glad you got it sorted out.

[G-ManBart]

Yup, you guys got it. The sizing die wasnt down all the way. Never a problem with all the lead I was shooting. I wasnt using an expander, and I couldnt put a bullet in by hand, but I guess the very small amount the sizer needed to be screwed down was enough to not hold the bullet.

I feel kinda dumb, but I guess it happens. Thanks for the replies and help.

It's a good chance that was the problem, but you'll still have to shoot some and see

[DWFAN]

What are some other causes and solutions to set back ? Maybe its not 100% fixed, but close.

I loaded 250 more tonight, and still had a few able to push in.(pushing hard against the front face of the bench). These were with Montana Gold again. I loaded some XTP, and those had no issues. The Montana Gold measure .355, The XTP's were the same. I can only think that the bullets may be slightly undersized or my sizing die is a little out of spec ? Im using the resizer, powder drop (no expander) and the seating die. No crimping, no FCD.

The issue seems to appear mainly with FC, PMC and Blazer brass, which Ive never had any other problems with and people say its good brass. The ID of the brass after sizing is .349

Has anyon heard of MG bullets being a little undersized ? Would .354 be enough to cause the issue? Ive got another case of MG I'll break open and try tomorrow.

[Sarge]

Did you MIC the bullets? There have been bad batches in the past if I recall. Not many, but it is possible.

There is a thread somewhere on MG bullets being out of spec. I would check every bullet to be sure. BUT, my money is still on the machinery. Probably a die.

[G-ManBart]

Has anyon heard of MG bullets being a little undersized ? Would .354 be enough to cause the issue? Ive got another case of MG I'll break open and try tomorrow.

I don't have any MG 124s to measure but I've certainly measured 115s and 121s that were .3545" (give or take a little). R

[LPatterson]

This may be making light of your problem but the guy goes to the doctor and says "Doc when I move my arm like this my shoulder hurts and the Doc says well don't move your arm like that." Your solution is to stop using the brass that is causing problems. Failing that buy a Lee 'U' die and screw it all the way down. A 9mm is a tapered case!

[Flexmoney]

Your FPS would not necessarily be higher, as the pressure can spike and dissipate before the bullet gets up to full speed and out the end of the barrel.

Where in the world are you getting that from?

The pressure is almost always at it's peak well before the bullet is up to full speed, or out of the barrel...heck, it may not even be out of the case when the pressure peaks (spikes).

I think you are saying the same thing.

[SA Friday]

Get rid of the FCD and use a regular seating/crimp die. Switch to a U sizing die. Your set-back problem will go away.

Edited March 12, 2010 by SA Friday

[DWFAN]

I havent been using the FCD since I noticed the problem. A U sizing die is on my list, but I'd like to see if I can fix the problem without it first.