10mm small primer pocket


December 23, 2011, 09:34 PM
If any one has any non toxic 10mm brass that has small primer pockets I would be interested in purchasing it. Pm me if interested.

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December 23, 2011, 11:10 PM
I have been making that same post for years, and have never been contacted, and I know they made some WINCLEAN brass that exists.

December 23, 2011, 11:16 PM
what's the draw to 10mm cases with small primer holes? I would be irritated with having to keep it perfectly separate from my normal cases so I don't crush a large pistol primer against it by accident.

I'd rather keep it uniform, but that's just me.

December 24, 2011, 01:30 AM
My schpealThe limit of pressure with most rimless cartridges is loose primer pockets. The 6mmBR class has primer piercing as a limit, as do many rimmed cases.

The weakest cartridge case head hall of shame:
1) 10mm has .334" extractor groove -.132" pocket/2 = .101" wall
2) 5.7mm has .254" extractor groove - .123" pocket/2 = .0655" wall
3) 30 carbine has .304" extractor groove - .123" pocket/2 = .0905" wall
3) 25acp has .247" extractor groove - .123" pocket /2 = .062" wall

The reason the shame is not in order of wall thickness is because the shame is proportional to case cross section area divided by wall area.

So if we had some small primer pocket 10mm brass, we could do some experimental loads with the 10mm that surpass the 40sw experimental loads.

December 24, 2011, 03:32 PM
Weld-up the 10mm casehead and machine a small primer pocket with a PPC flash hole ;)

December 24, 2011, 03:35 PM
Or drop in a small primer and seal with JB Weld.

December 24, 2011, 04:03 PM
What kind of experimental loads are you talking about? I like the ten, it is "the" handloader's cartridge for autos. I love tinkering with ten loads more than any other, just something about it. I actually got another 1006 yesterday, I told you I love tens.

Now I've ran 10.5gr. 800x with 180 Gold Dots, and I know folks have ran 'em a lot hotter, but 180gr. at 1344fps did it for me (and may actually be within pressure limits). I know a little bit about math and physics though, and what I know keeps me from comfortably going higher.

What I don't understand is what using the small primer will do for you. By the time you get to the point where the increase in case integrity matters in that area, you have already exceeded the pressure by far and it is no longer the weakest link (if it is to begin with). I understand the point of "experiment" and the value, but without pressure gear and a rig that can take it, why? And what is the goal of your experiement?

I know you were just looking for brass, but now you got me interested. I'm not knocking you by any means. I'm just real curious. If you are onto something, fill me in.

Personally, I have a great deal of interest in the .224Boz. Or a similar version, I think a 6 or 6.5mm would be cool in theory. I like long range handgun shooting, and the ten is a great platform to start with in this endeavour. Here I could see the value of a small primer, particularly a small rifle primer.

Whatever you do, good luck in it. I do have some advice though, have you tried calling Starline Brass? They will do custom order runs of brass, but you have to buy so much of it. Perhaps you could find others seeking them and make a group order. It wouldn't be hard, just run .40 brass and cut it longer, right? Wouldn't that suffice? I've seen the machines they use to make brass, worked with them (they were WWII machines upgraded and redesigned to make very high grade "plumbing" parts for nuclear and chemical plants where leaks are a no-go) and I can say for a fact it is very easy to make what you want.

If you had a revolver, you could load 180's or 200's in .40 brass with 10mm load data and COL. I've heard of folks doing this with .357's. You may find what you need to know without actually resorting to custom brass.

But from what I've read, the large primer is an asset and not a drawback. Some folks take 10mm brass and cut it to .40 length, but I don't see the value in this either. Personally anyway.

I also seem to recall some rifle brass is ideal for making 10mm brass from. Can't recall the calibre or what size primer it has, sorry, I just read about somewhere.

December 24, 2011, 05:54 PM
He's talking Cassull performance from his 10mm.

December 25, 2011, 02:29 AM

About 8 years ago I tried making 10mm brass from 30-30 brass, but it did not hold enough powder.

Oi, look at that lousy stock Glock 20 case support.

December 25, 2011, 02:18 PM
You are so right Clark. One slightly warm load in 10mm and new brass is loose. I recentley did some tests in my 6 inch wolf barrel, 40sw, glock 20 to prove to myself that I was not imagining the stronger pocket in the 40 caliber. Here are some of the velocities with the 40 case. 800x powder: 10g with 180 = 1439 avg. 10g with 155 = 1416 11g with 155 = 1573 It is noteworthy that the 800x liked the heavier bullet so much that it actually chronos higher than with the 155...I suppose it gives the powder more burn time(just my uneducated theory). The pockets are still tight on these rounds and not visible case distortion). The same loads in 10 mm loosen the pockets right away. I have a call into Starline to see if I could get some 40 sw with longer cases. I am not trying to get nuclear loads but have become a 40sw fan since I get the performance of the 10 with free brass laying around everywhere. Here are some loads that I use in my sig226 40sw: 7.2 unique with 180 = 1150 7.2 with 155=1270 7.3 with 180 = 1187 800x 8.0 with 180 = 1060. I do not recommend these loads to anyone else. They work for my situation. The brass is in good shape from the sig also. Thanks for reply Clark.

December 25, 2011, 02:22 PM
You could attempt cutting down and reaming small primed 6.8spc brass

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December 25, 2011, 08:06 PM
I will try that. Or another rifle cartridge. Thanks RW.

December 26, 2011, 07:37 PM
Here are some loads that I use in my sig226 40sw: 7.2 unique with 180 = 1150 7.2 with 155=1270 7.3 with 180 = 1187
The interesting thing I notice here:
Alliant lists max charge of 6.7 gr for a 180 gr GDHP, velocity around 1000 fps. You've exceeded the max charge weight by about 10% and you're getting 15% higher velocity. If it works for you, that's great.

But they list max charge of 8 grs for a 155 gr bullet! You are getting higher than the listed max velocity with only 7.2gr, and it sounds like you worked your way up to that. That's 10% below the max load. Is your load data a typo? Or is Alliant's data really that far off? If you were to use the old 10% rule, then this 1270 fps load is a starting load! (I also find it curious that you'd end up with a greater charge weight for the heavier bullet).

December 27, 2011, 10:50 AM
My only explanation is the completely filled case with a little compaction going on with the larger bullet. One of the reasons I came up with the name "casefull" was this. In general I have noticed more efficient use of powder when the case is completely filled. I believe the powder burns better. This seems to be generally true with rifles also. I think this is why I get better performance from the unique than the 800x up until the point the charge gets heavy enough with the 800x that it is getting compressed...ie the 800x does not do as well as unique until the charge is filling the case whether from longer bullets or higher charge amounts. I believe this is why you get more energy from a 40 with 7g powder than a 45acp with 7g of same powder and similar bullet wts. The 45 case will not be full of powder with a 185g bullet. I am not intending to be scientific or to prove this to anyone but my observations prove it for me. I agree the pistols shoot nicer with lighter loads than I am using.

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