Need answer on 9mm Mak. brass - The Firearms Forum

ransom63 · 12-31-2011, 03:06 PM

I've been trimming down 9mm brass for my Makarov reloads. I took some rounds to the range yesterday & they're keyholing. I rechecked my dimensions.The length of the brass SHOULD measure .705" & my resized brass was cut to .700". Also, the crimp standard should be .390" & my crimps are at .387" ( the crimp is done in a 3 die procedure- no seperate crimp die)
Now here's my question; can these extremely small differences in the brass (.005") AND the crimp (.003") cause the keyholing? They seem to be such insignificant differences from the called out dimensions that I thought maybe there would be that much tolerence for them.
I've already trimmed about 200 pcs. of brass to the .700" size. Is this brass trash?

JLA · 12-31-2011, 03:10 PM

Keyholing is cause by insufficient bullet RPM. 2 ways this can happen.. #1 the barrel simply doesnt have a fast enough twist and the bullets are destabilizing and tumbling to the target. and #2 the bullets are too small for the bore (i.e. youre using .355" bullets intended for the 9mm and .380 in a makarov which normally uses a .365" bullet..

So which is it?

res45 · 01-01-2012, 08:53 AM

I've only experiences keyholing twice in about 30 years and both times it was because the bullet was to small in dia. to engage the rifling,both were with swagded lead bullets that were to small for the bore to begin with.

The Speer reloading manual has a trim to length of 0.703 and a max case length of 0.713 and that's using commercial Starline brass in a Bulgarian Mak. Hornady list and E. German Mak. with at Max case length of 0.713 and a trim to length of 0.708. I shoot for 0.705 when I trim my case with my Lyman power trimmers but some end up +/- 0.002.

I shoot a PA-63 chambered in 9 x 18 Mak. and form all my brass from once fire 9mm brass of various brands. I shoot two bullet Speer .364 dia. 95gr. GDHP and cast lead .365 dia. 93 gr. RN. The GDHP and cast bullet both crimp at 0.387 incidentally the Brown Bear FMJ steel case ammo has a 0.386 crimp and the case length measures 0.702" before firing.

Mak. bores can vary I've seen some as small as .363 up to .366 dia. A little more info on your load data might be helpful in helping to determine the problem ie,bullet dia. and type,powder and charge weight.

Alpo · 01-01-2012, 10:26 AM

I'm gonna have to throw in on "you bought '9mm' bullets, but you bought the wrong size" bandwagon, and say that you are using .355 bullets.

RandyP · 01-01-2012, 11:01 AM

I wouild chime in and add that I have never trimmed a single piece of pistol brass. IMHO it is not necessary in the four calibers I reload.

ransom63 · 01-01-2012, 10:17 PM

OK, here's some more detail..
I'm using the Speer .364 dia. TMJ, with Universal powder, 4.1 grns. My crimps are @ .387". The pistol is the CZ 82. I've forgotten what the term is, but the CZ82 doesn't have the typical land & groove bore.
Can the case length be a factor?

Alpo · 01-02-2012, 07:05 AM

No. A too-short case might not fire, as the case headspaces on the mouth, and if it was waaay too short then the firing pin might not reach the primer, or if it did, be at the end of its stroke and not hit hard enough to pop it.

But keyholing is a bullet/rifling problem. Brass length has nothing to do with it.

JLA · 01-02-2012, 07:14 AM

Ive never owned a CZ82 9 mak but I have a CZ83 in .380 and it does have a cut rifled bore. Perhaps yours is either very well used and simply shot out or it is the aftermath of an experiment gone wrong.. Might slug the bore and take some measurements. Im bettn you will find it is extremely oversized.

RandyP · 01-02-2012, 10:42 AM

As part of my troubleshooting protocol, how does the CZ-82 shoot with any brand of factory ammo? If OEM ammo doesn't keyhole then at least we can be sure that the problem lies somewhere in your reloading process.

ransom63 · 01-02-2012, 04:44 PM

The CZ 82 has a polygonal barrel. The last time I shot OEM, the rounds made perfect round holes, so there has to be an issue with my reloading. It's going to be a couple weeks before I can reload another batch, so between now & then I'll review all my dimensions so everything will be dead-on spec.

res45 · 01-02-2012, 06:10 PM

My shooting buddy has the CZ-82,the only commercial ammo he shoots in it is Russian steel case and it does fine with that. His reloads are strictly Lee 95 gr. .366 dia. cast bullets shot as cast,they also shoot just fine. I'm thinking the .364 dia. bullet may just be to small and with less resistance in the smooth bore and being jacketed it's not bumping up enough to stabilize.

Might want to try out some of the Hornady .365 XTP HP http://www.grafs.com/retail/catalog/...productId/6339

medalguy · 01-02-2012, 06:58 PM

Mike your bullets and let us know the diameter. I also trim 9mm Para down to use in my Mak and haven't experienced any problems with keyholing. I'd bet on the bullet diameter.

01-01-2012, 08:53 AM	#3
res45 V.I.P. Member Join Date: Sep 2007 Posts: 182	Re: Need answer on 9mm Mak. brass I've only experiences keyholing twice in about 30 years and both times it was because the bullet was to small in dia. to engage the rifling,both were with swagded lead bullets that were to small for the bore to begin with. The Speer reloading manual has a trim to length of 0.703 and a max case length of 0.713 and that's using commercial Starline brass in a Bulgarian Mak. Hornady list and E. German Mak. with at Max case length of 0.713 and a trim to length of 0.708. I shoot for 0.705 when I trim my case with my Lyman power trimmers but some end up +/- 0.002. I shoot a PA-63 chambered in 9 x 18 Mak. and form all my brass from once fire 9mm brass of various brands. I shoot two bullet Speer .364 dia. 95gr. GDHP and cast lead .365 dia. 93 gr. RN. The GDHP and cast bullet both crimp at 0.387 incidentally the Brown Bear FMJ steel case ammo has a 0.386 crimp and the case length measures 0.702" before firing. Mak. bores can vary I've seen some as small as .363 up to .366 dia. A little more info on your load data might be helpful in helping to determine the problem ie,bullet dia. and type,powder and charge weight. Last edited by res45; 01-01-2012 at 08:55 AM..

01-01-2012, 10:26 AM	#4
Alpo Advanced Senior Member Join Date: Feb 2007 Location: NW Florida Posts: 8,666	Re: Need answer on 9mm Mak. brass I'm gonna have to throw in on "you bought '9mm' bullets, but you bought the wrong size" bandwagon, and say that you are using .355 bullets. __________________ Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297 I always take precautions. Beware the Evil Bullet Fairies.

01-01-2012, 11:01 AM	#5
RandyP V.I.P. Member Join Date: Jan 2009 Posts: 430	Re: Need answer on 9mm Mak. brass I wouild chime in and add that I have never trimmed a single piece of pistol brass. IMHO it is not necessary in the four calibers I reload. __________________ Lee Anniversary and Lee Classic 4-Hole Turret, presently reloading .380, 7.62 Nagant (32-20), 9mm and 45ACP

01-01-2012, 10:17 PM	#6
ransom63 Member Join Date: Mar 2011 Posts: 24	Re: Need answer on 9mm Mak. brass OK, here's some more detail.. I'm using the Speer .364 dia. TMJ, with Universal powder, 4.1 grns. My crimps are @ .387". The pistol is the CZ 82. I've forgotten what the term is, but the CZ82 doesn't have the typical land & groove bore. Can the case length be a factor?

01-02-2012, 07:05 AM	#7
Alpo Advanced Senior Member Join Date: Feb 2007 Location: NW Florida Posts: 8,666	Re: Need answer on 9mm Mak. brass No. A too-short case might not fire, as the case headspaces on the mouth, and if it was waaay too short then the firing pin might not reach the primer, or if it did, be at the end of its stroke and not hit hard enough to pop it. But keyholing is a bullet/rifling problem. Brass length has nothing to do with it. __________________ Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297 I always take precautions. Beware the Evil Bullet Fairies.

12-31-2011, 03:06 PM	#1
ransom63 Member Join Date: Mar 2011 Posts: 24	Need answer on 9mm Mak. brass I've been trimming down 9mm brass for my Makarov reloads. I took some rounds to the range yesterday & they're keyholing. I rechecked my dimensions.The length of the brass SHOULD measure .705" & my resized brass was cut to .700". Also, the crimp standard should be .390" & my crimps are at .387" ( the crimp is done in a 3 die procedure- no seperate crimp die) Now here's my question; can these extremely small differences in the brass (.005") AND the crimp (.003") cause the keyholing? They seem to be such insignificant differences from the called out dimensions that I thought maybe there would be that much tolerence for them. I've already trimmed about 200 pcs. of brass to the .700" size. Is this brass trash? --> Last edited by ransom63; 12-31-2011 at 03:07 PM..

12-31-2011, 03:10 PM	#2
JLA TFF Moderator/Host Join Date: Feb 2007 Location: Heart Of Texas Contributor Posts: 17,328	Re: Need answer on 9mm Mak. brass Keyholing is cause by insufficient bullet RPM. 2 ways this can happen.. #1 the barrel simply doesnt have a fast enough twist and the bullets are destabilizing and tumbling to the target. and #2 the bullets are too small for the bore (i.e. youre using .355" bullets intended for the 9mm and .380 in a makarov which normally uses a .365" bullet.. So which is it? __________________ It takes 43 muscles to frown, 17 to smile, and 3 for proper trigger squeeze. The latest caliber or gear is no substitute for experience and skill. Rifles and cartridges don't make hits -- shooters do. Fact of life: After Monday and Tuesday, even the calendar says WTF!

01-02-2012, 07:14 AM	#8
JLA TFF Moderator/Host Join Date: Feb 2007 Location: Heart Of Texas Contributor Posts: 17,328	Re: Need answer on 9mm Mak. brass Ive never owned a CZ82 9 mak but I have a CZ83 in .380 and it does have a cut rifled bore. Perhaps yours is either very well used and simply shot out or it is the aftermath of an experiment gone wrong.. Might slug the bore and take some measurements. Im bettn you will find it is extremely oversized. __________________ It takes 43 muscles to frown, 17 to smile, and 3 for proper trigger squeeze. The latest caliber or gear is no substitute for experience and skill. Rifles and cartridges don't make hits -- shooters do. Fact of life: After Monday and Tuesday, even the calendar says WTF!

01-02-2012, 10:42 AM	#9
RandyP V.I.P. Member Join Date: Jan 2009 Posts: 430	Re: Need answer on 9mm Mak. brass As part of my troubleshooting protocol, how does the CZ-82 shoot with any brand of factory ammo? If OEM ammo doesn't keyhole then at least we can be sure that the problem lies somewhere in your reloading process. __________________ Lee Anniversary and Lee Classic 4-Hole Turret, presently reloading .380, 7.62 Nagant (32-20), 9mm and 45ACP Last edited by RandyP; 01-02-2012 at 10:43 AM..

01-02-2012, 04:44 PM	#10
ransom63 Member Join Date: Mar 2011 Posts: 24	Re: Need answer on 9mm Mak. brass The CZ 82 has a polygonal barrel. The last time I shot OEM, the rounds made perfect round holes, so there has to be an issue with my reloading. It's going to be a couple weeks before I can reload another batch, so between now & then I'll review all my dimensions so everything will be dead-on spec.

01-02-2012, 06:10 PM	#11
res45 V.I.P. Member Join Date: Sep 2007 Posts: 182	Re: Need answer on 9mm Mak. brass My shooting buddy has the CZ-82,the only commercial ammo he shoots in it is Russian steel case and it does fine with that. His reloads are strictly Lee 95 gr. .366 dia. cast bullets shot as cast,they also shoot just fine. I'm thinking the .364 dia. bullet may just be to small and with less resistance in the smooth bore and being jacketed it's not bumping up enough to stabilize. Might want to try out some of the Hornady .365 XTP HP http://www.grafs.com/retail/catalog/...productId/6339

01-02-2012, 06:58 PM	#12
medalguy Senior Member Join Date: Feb 2009 Posts: 585	Re: Need answer on 9mm Mak. brass Mike your bullets and let us know the diameter. I also trim 9mm Para down to use in my Mak and haven't experienced any problems with keyholing. I'd bet on the bullet diameter.