Thinner-walled 9mm brass?

[higgins]

Like many of us, I have found that I need to load at least .358 bullets in my 9mm pistol. I am trying to use thinner brass so that there will be less squeezing of bullets. I am already using a .38 spl. M-die so the brass will be expanded more than with 9mm dies.

Have you checked your 9mm brass supply to find out what brands of 9mm brass tend to run thinner in the sidewalls, if any do? My check with a caliper ( don't have a suitable micrometer for such measuring) indicates that Blazer may be a hair thinner than most.

[tazman]

I haven't checked 9mm brass specifically. That said, Remington brass has always been thinner in the handgun cases I have checked.

[Kenstone]

I have loaded 9mm bullets up to 0.357" in assorted range brass and have not had any failure to plunk test to date.
I have 4 different barrels to plunk test, with the tightest/shortest chambered being a Storm Lake aftermarket barrel for a glock.

Remington-Peters (R-P) brass has an old reputation of being thinner and other brands have shown to be thinner for some, like Blazer, Speer, and FC.
I just ordered some 0.358" coated bullets for 9mm, looking for better accuracy, and may run into the same problem as you.

I'm looking to get as good or better groups than I get with 0.355" dia. jacketed bullets.
I did see some improvement going from 0.356" dia to 0.357" coated.
I looked at the sammi specs for 9mm cartridge and chamber to determine the max case wall thickness with a 0.358" bullet that will plunk in the standard chamber and I think that bullet dia will work with most range brass, I'm hoping anyways...
Sammi specs:
https://saami.org/wp-content/uploads...dR.pdf#page=10

edit: the chamber dia.'s are all +0.004/-0.000.

[fatelk]

I usually sort my 9mm brass for cast bullets, and use only U.S. commercial brass.

[Taterhead]

In 9mm, FC brass is what I seek for .358" cast boolits. it is the thinnest from what I've seen, and will more reliably kerplunk. A close second are Win/WCC headstamps.

For some reason, in other cartridges, R-P tend to be thin but they are very thick in 9mm. And European headstamps, + the Brazilian stuff tend to be thicker walled in 9mm.

[toallmy]

Doesn't the WCC 9 mm brass have a step shoulder inside ?

[razorfish]

Doesn't the WCC 9 mm brass have a step shoulder inside ?

Nope. WCC 9mm is good brass but you’ll have to swage the primer pockets.

IMT, Ammoload, FM and Maxtech 9mm brass have steps in them to prevent bullet setback... They go straight into the recycle bucket when I see them.


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[Ed_Shot]

I load for 8 different 9MM's and size all to .358. I have two "dedicated" Lyman M dies each set to the depth I want for expanding 9MM. I first expand with a 38P (.356 dia) plug and expand as deep as possible and still have the case plunk into a Lyman 9MM chamber gauge. The nose of the 38P plug is too long to allow it bell the case mouth. Then on a second pass I use my other M die with a 38AP (.354 dia.) plug to bell the case mouth. I keep several K 9MM brass expanded and ready to prime. My 9MM brass stash (buckets of it) is all separated by headstamp and culled to length .752" - .748" (what else do you have to do on a rainy day?). I'll say once again, I don't know how to work with 9MM brass that varies in length from .756" to .738". Anyway, I taper crimp so that the loaded round plunks in my chamber gauge and find that all the various 9MM chambers I load for are happy and bores lead free. I have never given any consideration to how thick the brass was. My 2 cents.

[marek313]

I'm still chasing this cast 9mm unicorn myself. I started to sort 9mm brass and I only keep major brands (Win, FC, RP, Blazer some spear and CBC). Ever since I think my 9s are shooting more consistently. Still not exactly as accurate as my 10mm or 45acp but better then before. Thick brittle brass def doesnt help with cast.

[toallmy]

I have 3-4 gallons of WCC brass for 9mm and it has a ridge at around 0.18 down that shows as a bugle when loaded with over sized deep seated cast boolits , but it is nice brass . You are correct I miss spoke when I stated step shoulder I should have said ridge instead .

[mdi]

Just wondering; does your .358" bullets get swaged down by the brass you're using now? I have a 9mm that prefers .358"+ bullets and my alloy isn't so soft mixed brass doesn't swage any (12-14 BHN)...

[higgins]

I haven't pulled any loaded bullets to see if they're swaged down. I'm using wheelweight bullets so possibly not, given that I'm using a .38 spl. M-die. I noticed differing effort to seat bullets in various brands of brass. I want to select a couple of brands of thinner brass to lessen the possibility of bullet distortion, and I wondered if my cursory check of brass thickness agrees with what others have found.

[mdi]

I haven't given much thought to case wall thickness in my 9mm brass because I have no reason to be concerned. Measure some of your bullets and seat them in the thickest walled brass you have, then pull them and remeasure. Know for sure if you have a problem before you try to solve one...

[Kenstone]

I haven't given much thought to case wall thickness in my 9mm brass because I have no reason to be concerned. Measure some of your bullets and seat them in the thickest walled brass you have, then pull them and remeasure. Know for sure if you have a problem before you try to solve one...

… and plunk test them before pulling them
Pulled bullets also give a good indication of the amount of crimp, I back off until there's no ring mark on the bullet.

I'm using a Lee 38 S&W expander plug in the Lee 9mm powder thru expander die when loading 0.357"/0.358" dia bullets
https://leeprecision.com/pm-expan-plg-38-s-w.html

[tazman]

Brass thickness variations is one of the reasons I water drop all my 9mm boolits. I may not need it, but the extra hardness is not going to hurt anything.
I always size to the largest diameter that will chamber in my pistols.
I only have one pistol that will not accept .358 diameter boolits in mixed brass 100%. It has a match chamber and gets fed .3565 boolits. That is what it shoots the best.
The others get boolits sized .357-.359.

[winelover]

I too separate my 9mm brass by headstamp for my half dozen nines. I never was concerned with different thickness in the case walls. Been doing quite a bit of accuracy testing with my CZ Scorpion carbine. Whenever, I find a decent load with a particular brand of brass, I will retest with several other brands of brass to confirm and compare. Most of the time, RP brass, yields the least accurate groups, whether it be with cast or plated bullets. All my cast bullets are sized to .358 diameter.

Winelover

[mdi]

… and plunk test them before pulling them

Nope, just testing case/bullet fit. Seat a measured bullet. Pull and measure. No need to plunk or anything else, and no crimp. Trouble shooting needs to be done in a systematic, step by step, one step at a time. Other wise you won't know which step has done what...

[Kenstone]

Nope, just testing case/bullet fit. Seat a measured bullet. Pull and measure. No need to plunk or anything else, and no crimp. Trouble shooting needs to be done in a systematic, step by step, one step at a time. Other wise you won't know which step has done what...

Awesome

[Conditor22]

My foreign 9MM's require .359-.360 cast boolits where I can get away with .356-.357 for my US guns.

[Bmp4510]

… and plunk test them before pulling them
Pulled bullets also give a good indication of the amount of crimp, I back off until there's no ring mark on the bullet.

I'm using a Lee 38 S&W expander plug in the Lee 9mm powder thru expander die when loading 0.357"/0.358" dia bullets
https://leeprecision.com/pm-expan-plg-38-s-w.html

I’m with Kenstone. I’ve two P226’s, shot lousy with cast bullets. I also have Springfield 1911 that was extremely accurate with my cast bullets. I worked on the two P226’s for three years with different loads, bullet diameters, powders, etc, to no avail. I purchased the Lee 38 S&W expander, swapped it into the Lee power through expander die, did the plunk test to determine the COL. Once everything was set, I now get one, ragged 10 shot hole at 10 yards. I wished my eyes were better, I’d test at 25 yards.

The same loads reduced the accuracy of the Springfield however, as the COL is quite a bit shorter for the P226’s. So my next task it to determine the COL for the Springfield, make a dummy round for it, and one for the Sig’s, so I can set the COL for the different pistols. PITA, but unless I want to have the Sigs reamed out to match the Springfield, not sure what else I can do. Finally caught the elusive 9mm cast bullet unicorn, at least for my 9’s.


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