9mm Major (or Minor) Problems Info Wanted

[MTrout40]

MTrout,

Your slide is milled to 9oz. Got pics? I'll trade for some pics of some sick Mopars.

Steve

<{POST_SNAPBACK}>

Yes sir...9.2 with firing pin and extractor. The best part is that was with NO holes in the slide! Ok, well I put 2 in the top in case of future barrel ports but that doesn't count. LOL I have a few pics but I can take more with the digital if you would like. And I would love some Mopar pics! I just found a vid of a twin turbo Cuda running 8's!! But I guess we'll save that for email chat.. hit me up at mtrout40@yahoo.com and I'll send some pics.

MT

[Guy Neill]

You might check Alma's post above. He has experienced his Glock cracking the breechface using 9mm Major. I have not seen any other cracked slides personally. I've been told Bob L has seen some, but I have not had a chance to talk to him about it.

In the past, I have seen 1911 45's crack slides. It was either at the ejection port, as someone else described, at the left rear corner, or at the end of the lightening cuts at the bottom front of the slide (when everyone was shoting 5" 45's). One reason Colt removed the bridge of metal at teh slide stop cut out on the Delta Elites was because of the tendency of that bridge to crack. Another area that has cracked is at the rearmost portion of the dust cover, though this commonly has more to do with the way the gun was fitted. Strangely, as I think about it, I don't recall ever seeing any cracks on the right side. They've all been on the left side of the slide and frame. Okay, I take that back, I do recall an early Detonics that had a frame crack in the grip area on the right side.

When the lead free ammunition first began selling, I also saw breech faces that were peened by the primer in various guns. Ultimately, I expect they would have cracked as Alma described. This will likely be common on any guns where the slide is case hardened instead of through hardened and the breech is pounded by the primer.

Slides with lightening cuts may have a slightly greater tendency to crack, depending on where the cuts are, and their configuration. Even if there is no stress raiser from the cuts, the increased slide velocity may see greater impact that could lead to increased stresses or wear.

Like any tool, however, the guns are subject to wear and will need maintenance and repair if they are used. Every sport has its price, and periodic repalcement of parts or guns is part of our price if we are actively shooting. It's important to inspect the gun and all the pieces when you clean the gun to find things as early as possible.

Guy

[Guy Neill]

Eric, I understand your concern with the 40. As I tried to point out in a column many years ago, the hoop stresses in the 40 are greater than for a 9mm simply because of the larger diameter (at the same pressure).

Many of the earlier 40 probelms I believe also related to the amount of material in the cases. Some of the earlier cases had relatively flat bottoms inside, minimizing the amount of brass at the transition between the web and case wall. This is the exact point where they were blowing out. While I can not say with absolute certainty, I believe the factories have changed the 40 cases, adding a radius at the inside bottom, allowing more material in the case web to wall transition. I do know that the number of blown 40's I saw while still with Speer reduced significantly in recent year, indicating, to me, that something had changed. Still, there is still ammo out there with the old case style and, I'm sure, in the reloading arena, so care should still be exercised.

Take care.

Guy

[Paradox]

While I don't have any 9mm load data to provide, I do have an observation that might be relevant.

I am pretty anal about loading my .308Win match rounds, as a result I have weighed and measured case volume on lots of cases. Basically, I have found that case weight and case volume are not always related. The extra mass could come from areas that do not affect its volume.

Filling cases with water and the associated process isn't something on my fun list, so I never tried it on pistol cases. Perhaps there is a similar correlation with the 9x19 cases?

[Guy Neill]

Quite right. The original premise was that the added weight was assumed to affect the internal volume. As has been demonstrated through water volume, the added weight does not always greatly affect the internal volume. Rim diameter and thickness, along with the diameter of the bottom of the extractor groove can affect weight without affecting internal volume.

Thanks.

Guy

[George]

9major is nothing new really, it's just allowed again. IMO, it was fairly safe at 175+ PF using 124 and 130 gr bullets at short loaded lengths in the P9 back in the early 90's. It's even safer now at 165+ PF in S*I pattern guns at long loaded lengths.

I caveat the 9major situation with the cautions that brass should always be a carefully controlled factor (don't just use range fodder, you wouldn't do that with .38 super, would ya?) and that 115 grain projectiles are only for very experienced reloaders in a caliber with this small of a case volume (I am very experienced and I would not do it).

I have been using the old 9x21 P9 standby load from circa 1991. It's a 124 grainer loaded 1.135" OAL over WW 540 for just under 10k now in a Glock 17L with the stock slide and a ported Barsto bbl. I use one batch brass from a single supplier. No problems whatsoever, so far ;-)

I would use 9x19 if I weren't already chambered for 9x21 in that bbl, but I would never use range brass at major PF, especially in competition usage. Again, I wouldn't use range scrounge, or odd lot purchase for a .38 super comp gun, so why do it with a major 9 comp gun that I put the same type of bucks into. We build these blasters up to run reliably and safely, right!

No BS, this is not cutting edge stuff, it's bleeding edge stuff. So be very careful please!

Thanks for looking at this issue Guy.

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Regards,