Brass bulge...how much is too much?

[sqlbullet]

Bulged is usually not a problem, even if the bulge is large.  Cold working the brass makes it stronger.

Smiled is usually a problem.  The smile line is where the brass started to separate, tear or crack. Even if you mechanically move the brass back, it will not become one uniform piece again.

[Mike D]

Bulged is usually not a problem, even if the bulge is large.  Cold working the brass makes it stronger.

Smiled is usually a problem.  The smile line is where the brass started to separate, tear or crack. Even if you mechanically move the brass back, it will not become one uniform piece again.

Good and pertinent discussion here. I just worked up some 200 grain Gold Dot loads with BE86.

Glock 20 long slide, 6.5" Lone Wolf barrel
24# recoil spring
Average case length - .977
COAL - 1.250
Once fired Sig brass
Load steps
8.0 - Avg 5 shot velocity 1278.87
8.2 - Avg 5 shot velocity 1308.71
8.4 - Did not shoot
8.6 - Did not shoot

I've shot thousands and thousands of 10mm with factory, LW and KKM barrels and I have never seen a smile on a case until now.





I'm assuming these are a weeee bit hot. I think I'll back down to around 7.4 grains and try again.

I sure wish Quickload had BE86 powder in its database. [emoji853]




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[The_Shadow]

Muskrat, great pictures of the brass and cut away too...   Starline brass does start out softer (Underwood is using brass from Starline but with his own headstamp).  As such the brass is more useable as handloader but it will work harden over several uses.

Winchester brass was stiffer and less malleable but seemed to hold up better under higher pressures than some other brands.
Hornady & Federal were always on the stiff side and I have seen many Federal cases split long ways when fired in the HK MP-5 10mm guns.  Out of 500 about 55 or 60 were split or split while resizing.

Here is another thought, Starline makes the 10mm Magnum brass which is a little thicker around the base and up the case walls, if cut and used for 10mm Auto it may provide better strength but have issues when seating the longer bullets in the thicker cases.  (The 10MM Magnum Brass is a heavy duty, lengthened 10MM Auto. CANNOT BE USED IN STANDARD 10MM PISTOL.)
I knew some guys that trimmed them to 10mm Auto lengths and used them. 
Not sure if they would bulge less with the same loads in the Banshee.

[Muskrat]

Interesting idea to try the 10mm Mag brass...might be just the ticket for 165 grain loads. A 165 Blue Bullet over 9.7 grains of Power Pistol is a fantastically accurate load in the Banshee, but it's right on the edge of bulging the brass to the worry point.

[BENTENMM]

Just a quick mention on the 6.8spc brass.. Yeah, that would be a big no go in my book. I cut some down at various lengths.. .997" being the max. Reamed them to .395" (not doing so will cause bullets to be crushed and brass to be severely bulged because of 6.8spc wall thickness at base) just deep enough for bullet seating.

After testing a half dozen variations of length and reaming depth/upper wall thicknesses. I've come to the conclusion that the loss of case capacity does not justify the added strength of the brass @ the base. In one case I noted a capacity of 3.2gr less when compared to a piece of new starline brass of the same length. Therefore pressures for the same desired velocities are much much higher.. and if you were looking for something that could handle more of a beating with less support.. 6.8spc isn't gonna do it.

I'm going down the 10mm Magnum path to see if that's an option.

p.s.

I ran the 6.8spc brass numbers through quickload.. .990" 22gr case capacity 170gr precision coated bullet .595" seated @ 1.265" over 9.7gr PP =  112% fill 1547fps 8" Barrel  908fpe  47,853psi !!! 34,603psi from Multi X fired FC .988" 24.3gr capacity.

[sparkyv]

Excellent sectioning, Muskrat.  We can all learn from your work. My opinion: Based upon the results of your study, I would reload that bulged brass all day long, perhaps only for warmup loads if I was being overly conservative. Well done, sir.

[Muskrat]

Thanks sparkyv!

I think the key is having a decent macro lens. I agree that reloading these pieces is safe enough to proceed with.

cheers

[PointBlank82]

So I picked up my Banshee 300 today.

Any updates on brass life reloading the Banshee Bulged cases? I don't see the need to push any speed records on my Banshee and want to work up a moderate target load with a little more recoil than standard S&B 180 gr FP.

I saw that 165 gr FMJ with 9.7gr Power Pistol reportedly is on the verge of bulging... has anyone use any of the slower magnum powders like AA#9? I have a large variety of powders to choose from and want a economical target round to make a few cases of.

[Muskrat]

You'll just have to experiment. I've noticed a lot of difference with the brand of brass, and how many times the brass has been reloaded. Blue Dot seems to work pretty well...10 grains with a 180 grain bullet, or 8.5 grains with a 200 grain bullet have not bulged any brass for me. Slower powders might help some...when I get motivated I'll work up some loads with AA#9 and see if there's any difference.

When they do bulge, I've found that if they'll go through the resizer they're ok to reload, for range loads anyway. Hot loads...book max or Underwood level loads cannot be resized, though I've yet to have one rupture or separate. I use the 8oz buffer for everything, which might be why I haven't had any of the separations other people have reported.

If I ever find a small bag of 10mm Mag brass I'll try cutting it down and see if it's any stronger than regular brass.

[slayer61]

Bulged is usually not a problem, even if the bulge is large.  Cold working the brass makes it stronger.

Smiled is usually a problem.  The smile line is where the brass started to separate, tear or crack. Even if you mechanically move the brass back, it will not become one uniform piece again.

Good and pertinent discussion here. I just worked up some 200 grain Gold Dot loads with BE86.

Glock 20 long slide, 6.5" Lone Wolf barrel
24# recoil spring
Average case length - .977
COAL - 1.250
Once fired Sig brass
Load steps
8.0 - Avg 5 shot velocity 1278.87
8.2 - Avg 5 shot velocity 1308.71
8.4 - Did not shoot
8.6 - Did not shoot

I've shot thousands and thousands of 10mm with factory, LW and KKM barrels and I have never seen a smile on a case until now.

pics removed...

I'm assuming these are a weeee bit hot. I think I'll back down to around 7.4 grains and try again.

I sure wish Quickload had BE86 powder in its database. [emoji853]




Sent from my iPhone using Tapatalk Pro

Where did you get the idea that 8.0 of BE-86 was a good start point for 200 grain projectiles? Alliant doesn't list a 200 grain bullet, only a 190 and and the max with a 190 is only 7.6?

[The_Shadow]

Slayer61, I have worked up my own load using the 200 grain Gold Dots using 8.4 grains of BE-86, however I setteled on 8.3 grains at 1200 fps with the 200 GD.   
Aliant's data is very low for the BE-86 and they stopped adding the pressure values.
Also have seen some recent commercial loads using BE-86 as documented...