Wednesday, May 19, 2004

I thought I would post some notes on my 10mm Auto barrel from posts I made on the Specialty Pistols forum.

I have a 14" that I got from the old obsolete barrels list. I put a Choate extension on it and use it as a carbine barrel. I had some interesting results from my chrono run on my 14" barrel.

10 gr. Unique 155 XTP/1156/460/55/67
155 XTP Factory/1457/731/5/7
180 Hydroshock Factory/1093/477/39/54
180 Rem HP Factory/1180/556/20/27
10 gr. BlueDot 180 BullX TC/1510/911/10/16

Factory ammo sure ain't a barn burner!

Reference, pierced primers. This is interesting. I noted that some loads, and not the hot ones, have a tendency to have that look to the primers although none were actually pierced. You know, that just about pierced look. I haven't seen such primer appearance with any other cartridge regardless of pressure level. Of course all these were fired on the same frame. RELOADS don't exhibit this only FACTORY ammo. Peculiar.

I'm really getting to like the 180s in this cartridge. Guess what, just like the .38 WCF (aka .38-40).

BTW, another interesting observation. At 150 yards, all loads struck to within 3 inches of one another. My 14" with Choate extension, used as a carbine, TC aperture sight. That's with loads of 155 going 1100 fps to 180s going 1450 fps!

I can see why this level of performance had a following. Low recoil usable trajectory to 150 yards (and farther if you are have some experience), sufficient power for close range hunting but not excessive for small game and relatively low report. Would be a great cartridge to teach a youngster and transition to centerfire.

Found a box of PMC 170 gr. factory stuff and shot it up today. 1292/630/17/26 (fps/fpe/ad/sd)

I'm constantly amazed at the velocities I'm not getting. The bore expansion ratio is such with this cartridge that it does just a hair better in the 14" than it would in the 5".
Wanted to let you know the results from my 10mm Auto loads with the 180 gr. XTP and 10.4 gr. Blue Dot. I got 1271/646/23/32 (fps/fpe/ad/sd).

My load with the old BullX 180 gr. TC cast got 1510 fps with 10 gr. of Blue Dot. A little faster I can see but 239 fps! I'd like to know what is up with that. Well that is what makes this interesting. It is accurate.

Of course it is more accurate when the darn sight (TC made aperture) doesn't fall apart while shooting! Apparently the elevation screw unscrewed itself. With my handy magnetic pointer I found it but what a pain. I'll be switching to the Williams WGRS shortly.

I crimp them pretty good and it burns noticeably "cleaner" than new Unique. Of course clean means different things to different people. Also, I can't remember if I said before, but I'm consistently getting complete burn with 10.4 gr. BD and the CCI LP primer (standard NOT magnum). The other day I kept looking down the bore for powder and didn't see any. I was also shooting over my ground sheet to catch whatever blows out of the barrel, but nada.

I am seating those XTPs to make a COL of 1.265" (average). It seems to vary some (I measured 15) and varies between 1.260 and 1.270. I haven't been able to figure out what is causing the variation but suspect that there is a minor variation in the bullet length (guess I'll have to measure the bullets now! ). I does NOT seem to be the result of high primers, headstamp "burrs", or bullet deformation.

I loaded these so that I could use them in a Delta Elite if I wanted (eventually ) without regard to the throat length. I'm off to the range this morning to zero this load and try it for groups out to 150 yards (range use allowing).

Took the new load and loaded it into Pointblank. That program says my PBR (Point Blank Range) should be 107 yards. Range tests prove it out. If you want a 150 yard gun in this caliber you need to go to the .41 Rem Mag or wildcat the 10mm on the .44 Mag. With the 10mm Auto you are down 10-12 inches at 150 yards.

Now when I shoot this out of a Delta Elite, it doesn't seem that bad because I can easily adjust but with peep sights (and probably with a scope) it is very noticeable.

However, it should still do in any farm pest like groundhogs, coyotes and such.

Accuracy? Well, with my sight set up it is no great shakes. On rocks or what have you I will hit them but on a bullseye (50 meter slow fire pistol) at 100 yards, the front post subtends so much that it is difficult to figure out how much side to side you have. Groups ran 5 shots into ½" vertically but 1-2" horizontally. That was the best I could do.

Set up for the PBR, you have to remember that you will be shooting noticeably over at 25-65 yards. This overage is 1-2" and can make the difference if you're attempting squirrel dinner. Again, for those farm pests, just hold center of mass and you'll be fine. This will work on 2 legged pests to 150 yards but much further would be a true desperation/time buying move.

Interestingly, this load of 10.4 gr. BlueDot supposedly runs 35K CUP or around 4400 for breach thrust. That's near the limit for the Contender (isn't it supposed to be about 4500?).

In any case it is a fun cartridge.

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