Need help with MG 115JHP's

[G17]

I'm trying to load Montana Gold 115 gr Jhp's right now with 5.4 grains of WAC. I can't seem to find a good OAL and i'm not sure how short i can go and still be safe.

I'v got three in a row that measure 1.111 that pass the drop test and spin. Then the next one will measure 1.111 but not pass the test and will not spin at all. I can't figure it out. Even if i drop the oal closer to 1.10 they still act like that. Some that are longer will pass the drop test and i'll get a few shorter ones that won't. It doesn't make any sense. Where should i be at on OAL?

I'v searched and searched and can not find anything that relates to what i am loading. Everything i find people are loading much longer and it seems to obviously not fit. This is going to shoot out of a glock 17 with a KKM barrel.

Also, i recently loaded 500 Xtreme Plated RN 124's at 1.150-1.160 and they all dropped and shot perfect. What am i doing wrong?

[G17]

I have a round that measures 1.097. It's hitting the rifling. This is just not making any sense to me when i have three others at 1.111 that spin fine. They all look fine, i mean i don't know why it's catching.

[atbarr]

Not sure about the 'Spin test', I have a full blown G17 by Zev. I load to 1.155 to 1.60, as long as they load into a mag, there good to go.

[G17]

When you drop a loaded round into the barrel chamber it shouldn't been sitting on the rifling, correct? Well if it's making contact with the rifling it won't spin. I'm just following the plunk test everyone talks about. Besides, the round ends up sticking back behind the barrel hood. That's what this is about.

With my prior loads with a 124 RN i could load to 1.160 no problem. With these JHP's they're hitting the rifling between 1.090-1.11. Just making sure it's safe to go lower then that.

I just loaded 10 rounds with 5.4 grains of WAC at 1.085. They all seem to pass, i just want to make sure that's not to short. Anything above that hits the rifling. I just can't seem to find any information on this topic.

Edited February 4, 2014 by G17

[Doug S]

Check your case walls and make sure they are resized. I'm pretty sure it isn't your OAL that's causing it. My 40 did the same thing and it was the cases.

Doug

[G17]

I resized and used the powder thru/expander die. Could it possibly have to do with my case flare? It seems like they're just enough flare to except the bullet so..idk. Everything looks good. It seems like at 1.085-1.090 they're consistently passing the plunk test. But anything over then that and it gets weird. I'll have shorter bullets hitting the rifling and longer bullets passing. It makes it hard to get a consistent OAL.

[Doug S]

Use a dry erase marker and cover the case and bullet on one that won't chamber, then drop it in and see where it is touching. This should identify the issue.

[SonOfSpartans]

Extractor marks on the rim of the case will catch too. Run your finger around the case and feel for burrs.

[rtp]

When you drop a loaded round into the barrel chamber it shouldn't been sitting on the rifling, correct? Well if it's making contact with the rifling it won't spin. I'm just following the plunk test everyone talks about. Besides, the round ends up sticking back behind the barrel hood. That's what this is about.

With my prior loads with a 124 RN i could load to 1.160 no problem. With these JHP's they're hitting the rifling between 1.090-1.11. Just making sure it's safe to go lower then that.

I just loaded 10 rounds with 5.4 grains of WAC at 1.085. They all seem to pass, i just want to make sure that's not to short. Anything above that hits the rifling. I just can't seem to find any information on this topic.

Max OAL for your gun barrel with different brand/weight/profile/type (HP vs RN, etc.) will be different across any/all/most of the combinations.

Either you're not re-sizing properly (die down to shell plate/re-read die instructions...I'm thinking this is less likely, though), you're loading too close to OAL on your bullet/barrel combo that some are causing issues, or you're not de-belling the cases enough.

Start here, and find your actual max OAL for that projectile and that barrel.

http://www.czfirearms.us/index.php?topic=34225.msg189131#msg189131

Then let us know what it is.

Tell us how you're setting up your resizing die?

What is the OD of the top of the case (just before the bullet is exposed over the case mouth) after the bullet is seated and the case is de-belled or crimped. It should likely be ~.377" or pretty close, but you can verify this yourself. Take calipers, measure the OD of a few of your bullets, in the general area you're seating/where it's meeting the case mouth or just below. MGs will be pretty consistent and close to .355"

Now, grab a case, and measure it's wall thickness at the mouth. Guessing it's ~.010" to .012" or so. Add them together, and that should be what you're aiming for, or just slightly under - 'crimping' is really 'remove the bell.' If your finished rounds are at .380" vs .377"-ish, you're not removing the bell/crimping enough.

I've got a KKM barrel in my Glock 19. The OE chamber would go longer than the KKM, but the KKM isn't particularly 'short'..I was loading 124gr MG JHPs to 1.085" but could have gone a bit longer if I'd wanted to.

Edited February 4, 2014 by rtp

[Justsomeguy]

As RTP pointed out, OAL is definitely gun and bullet specific. You seem to be right on the edge of what your gun will accept with MG bullets at your present OAL. If you shorten it a bit and are not at a maximum load at present it won't matter much, but if you are at or near a max load everything matters and you might have to reduce your powder charge a tenth grain or more depending on how deeply you must seat vs. the recommended powder charge. If the difference is not too great and they feed now they should still feed at the required OAL.

There is always the option of getting a throating reamer and opening up the chamber length some at the throat. With barrels with standard rifling this is a matter of a few minutes and a little cutting oil. It is an "in hand" operation requiring no machinery.

Edited February 4, 2014 by Justsomeguy

[G17]

Guys i'm sorry for wasting your time, im a dumb@ass. When i was doing the plunk test i wasn't using the crimp die yet. I figured the bullet seating die would crimp it enough that it wouldn't matter. Then i started measuring it and realised it was way too wide. Once i ran them through my lee crimp die and crimped to .375ish they all passed the plunk test.

I did gain some valuable knowledge from that link and determine max oal though and i am very happy about that. I took an a bullet and found an unsized spent case that would accept it snuggly yet still allow it to go in. I then did like the illustration said and pushed it into the chamber slowly then when it stopped i took a measurement.

It maxes out at 1.15(85).

It said back off .15 so bullet is not touching rifling. I pushed the bullet in just a tad and measured and i'm getting 1.15(30). It drops and spins freely, thats where my bullet seater is set. I just made up 20 rounds at that OAL which i feel very confident with. They all fit the mags/ chamber up, i racked them all through the gun, everything looks good! I'm pretty happy with this because last night it was frustrating the heck out of it. I had to just walk away, lol.

Thanks again guys

[lcs]

Your OAL is also affected by the mags. Make sure your rounds do not touch the front of the mags. 1.155 is about the max.

[Yardbird]

I can easily get out to 1.160

[G17]

Ya, i think 1.160 is about the max, i'm just trying to give myself a little room. I'm loading them at 1.155 now and all is well.

[Sandbagger123]

If you have more than one 9mm and intend to use those rounds in it, best to check the oal works in them also. i found out the hard way.

[G17]

Just out of curiosity, what happens if you accidently try to fire a bullet that is too long and into the rifling? Will it still fire properly and the issue will be with how it feeds and ejects?

Edit: after thinking about it for a sec, it probably won't be able to chamber properly and have the slide close all the way, right?

Edited February 5, 2014 by G17

[eric4069]

When you drop a loaded round into the barrel chamber it shouldn't been sitting on the rifling, correct? Well if it's making contact with the rifling it won't spin. I'm just following the plunk test everyone talks about. Besides, the round ends up sticking back behind the barrel hood. That's what this is about.

With my prior loads with a 124 RN i could load to 1.160 no problem. With these JHP's they're hitting the rifling between 1.090-1.11. Just making sure it's safe to go lower then that.

I just loaded 10 rounds with 5.4 grains of WAC at 1.085. They all seem to pass, i just want to make sure that's not to short. Anything above that hits the rifling. I just can't seem to find any information on this topic.

Max OAL for your gun barrel with different brand/weight/profile/type (HP vs RN, etc.) will be different across any/all/most of the combinations.

Either you're not re-sizing properly (die down to shell plate/re-read die instructions...I'm thinking this is less likely, though), you're loading too close to OAL on your bullet/barrel combo that some are causing issues, or you're not de-belling the cases enough.

Start here, and find your actual max OAL for that projectile and that barrel.

http://www.czfirearms.us/index.php?topic=34225.msg189131#msg189131

Then let us know what it is.

Tell us how you're setting up your resizing die?

What is the OD of the top of the case (just before the bullet is exposed over the case mouth) after the bullet is seated and the case is de-belled or crimped. It should likely be ~.377" or pretty close, but you can verify this yourself. Take calipers, measure the OD of a few of your bullets, in the general area you're seating/where it's meeting the case mouth or just below. MGs will be pretty consistent and close to .355"

Now, grab a case, and measure it's wall thickness at the mouth. Guessing it's ~.010" to .012" or so. Add them together, and that should be what you're aiming for, or just slightly under - 'crimping' is really 'remove the bell.' If your finished rounds are at .380" vs .377"-ish, you're not removing the bell/crimping enough.

I've got a KKM barrel in my Glock 19. The OE chamber would go longer than the KKM, but the KKM isn't particularly 'short'..I was loading 124gr MG JHPs to 1.085" but could have gone a bit longer if I'd wanted to.

Wow this is great stuff and very timely for me as I got my 550 this week and am trying to work up a load with MG 124 JHP. At OAL 1.100 the bullet still touches the rifling, but not at 1.090 (CZ SP01 Shadow Custom).

I will have to go throuth the OAL measuring procedure reccomended above.

Thanks!

Eric

Edited February 26, 2014 by eric4069

[lcs]

This is just to easy. It is so common sense. We get so wrapped around the axle we can't see the tire. RTP deserves the credit for posting it.

http://www.czfirearm...89131#msg189131

[rtp]

Wow this is great stuff and very timely for me as I got my 550 this week and am trying to work up a load with MG 124 JHP. At OAL 1.100 the bullet still touches the rifling, but not at 1.090 (CZ SP01 Shadow Custom).

I will have to go throuth the OAL measuring procedure reccomended above.

Thanks!

Eric

CZs are known to have shorter chambers.

I was surprised to find out that my PPQ does as well; had to reduce my 124gr MG JHP loads from 1.085" (could have gone longer in my Glock) down even further to 1.065" for my PPQ.

Much better to know what there is to know before loading vs after.

I remain quite glad I checked my PPQ barrel vs assuming 'it's already short, surely it'll work' and loading up a few thousand at the longer OAL...which I was considering doing.

[Steve RA]

If you want to load longer in a KKM, load up a dummy - no primer/powder - and ship it to them and they will ream it for you.

Minor charge, probably covers the freight back, call to verify.

If you have several I'd suggest trying to match them all up so you can use one setting on press for all.

[gose]

Wow this is great stuff and very timely for me as I got my 550 this week and am trying to work up a load with MG 124 JHP. At OAL 1.100 the bullet still touches the rifling, but not at 1.090 (CZ SP01 Shadow Custom).

I will have to go throuth the OAL measuring procedure reccomended above.

Thanks!

Eric

Seems to mimic what I see in my Tactical Sport and Czechmate with the MG 115 JHPs. I start hitting the rifling at 1.098 and I load to 1.088.

Edited February 26, 2014 by gose

[rtp]

If you want to load longer in a KKM, load up a dummy - no primer/powder - and ship it to them and they will ream it for you.

Minor charge, probably covers the freight back, call to verify.

If you have several I'd suggest trying to match them all up so you can use one setting on press for all.

Good to know, thanks.

As it is, the PPQ has a stepped chamber and would need to get that one reamed as well. Will keep in mind in the event I ever do a replacement barrel in the PPQ - the 1.065" OAL is accurate in both guns currently, so going to call the OAL as 'good enough' for now...as you said, one setting for both primary pistols.