bobclevenger

Yep, went out to the range to try out some loads in 9x23, .38 Super, .30 Mauser, and 10mm. I'll comment on the 10mm load here.

The pistol is an EAA Witness Compact with the 3.6" barrel that has been ported. It has a 20# recoil spring and a Buffer Technologies shock buffer installed. For what it's worth I have mounted the Compact slide and barrel on a full-size frame.


This is the load I tested:
Cartridge: 10x25mm
Barel length: 3.6" (ported)
Powder: 13.0 gr. HS-6
Bullet: 155 gr. Cu-plated lead
Cases: Mixed
Primer: LP (M)
MV: 1192
ME: 489
PF: 185

Everything worked just fine. Recovered brass looks almost like new.

I am a little bemused by why this load got 1192 fps and the last test load of 12.5 gr. of HS-6 (half a grain less) got 1217 fps out of the same gun over the same chronograph. Yeah, I realise that the two velocities are essentially equal, but the lower one uses 0.5 gr. more of the same powder. Yeah, I have been weighing each charge on these tests,

danf_fl

What was temp and humidity levels on both loading and shooting days?

In my "history", some reloads I did in summer that made major during the warm months, failed to make major during cold.

Different batches of powder can have an affect of muzzle velocities, too.

bobclevenger

Both days were in the high 50's or low 60's. Don't know about the humidity except that it never varies a lot here in Reno. These were from the same can of powder.

tsp45acp

Sometimes it has to do with burn consistency. A smaller charge may burn better than a heavier charge.....and whether the charge was closer to the primer when ignited (i.e. pointing the gun up vs. pointing the gun down prior to pulling the trigger. Also maybe the same powder, but different "lots" will burn slightly different.....Clean bbl vs. dirty bbl. A lot of variables. Just my .02 worth. Tracy

bobclevenger

I'm beginning to think that I've pretty much reached the maximum amount of HS-6 that can burn efficiently in a ported 3.6" barrel. Going to try a slightly faster powder next time.

Thanks for the ideas guys.

bobclevenger

OK, I have pursued this some more, trying a faster burning powder, namely Winchester 231.

Chronograph was 15-20 feet from the muzzle.

Cartridge: 10x25
Pistol EAA Witness (steel frame)
Barrel: 3.6" with porting
Powder charge: xxx gr. Winchester 231
Bullet 155 gr. Copper-plated lead truncated cone
Cases: Mixed
Primer:Large Pistol (Magnum)
MV:1293
SD: 41
ME: 575
PF: 200

Yep, pretty much a MAXIMUM load for this powder, but it does perform better in that short barrel. Cases look fine, but the primers are showing some flattening. This load works in my pistol, but it may not in yours. Start a bit lower and work up carefully, please.

I have been informed by a friend who has a computer program designed to estimate such things that the pressure developed by this load was over 100,000 psi. Not even I am that crazy. More work to do. That's why the powder charge has been removed.

retDAC

Interesting results. Thanks.

Alabaster

Nice. I don't have much experience with the 10, but that seems quick out of a ported 3.6in barrel!

May I ask? Is that a carry gun? I'd imagine that thing thumps with 155gr bullets. Very kewl.

bobclevenger

Yep, that is one of my carry guns. Thanks for the compliment.

Big-10mm

No offense, but your friend is wrong. Winchester sells the 175gr silvertip and it is rated at 1293 fps using the factory version of 231. A charge capable of generating 100,000 lbs (greater than the 30-06!) would explode the barrel.

I would estimate the charge in the low 30,000's. A good powder for the short barrel 10mm's is 800x or AA-7.