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.

Load/velocity/energy/AD/SD
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.

I've been reloading the 10mm Auto for my 14" Contender barrel. My preferred bullet is the 180 gr. XTP and I'm currently loading it with Blue Dot (BD).

I've been reading some of the posts on the forum and following links to a certain excellent site and see that I'm not getting the results that I ought to expect.

First, I've tried various bullets. Those I had the best accuracy results with (other than the preferred 180 gr. XTP) were the 155 gr. Hornady XTP and the 180 gr. BullX (sadly departed) TC cast. I also tried various powders including BD, Unique, and 2400. In other words a wide range of powders (although the AA powders are very hard to come by around here). BD seems to be the best powder for accuracy and velocity.

Combining BD and the 180 XTP I worked up to the Hogdon's Annual Manual max of 10.4 gr. of BD. Velocity from my 14" barrel was only 1270 some fps. Factory loads from Remington, PMC, Federal (Hydro Shock), and Hornady did no better. Of course the Hornady factory 155 gr. XTP loading was an exception and produced about 1450 fps. One notably surprising thing is that the BullX 180 gr. cast went 1458 fps (or so, I don't have my records here at work) over 10 gr. of BD. Now, I expect jacketed bullets to be a bit slower, but 200 fps?

Reading posts here and there and some associated files, I see that this performance is generally what can be expected from 5" barrels. That's kinda disappointing but not really.

My goal was to load the XTP to .38-40 rifle velocities, or about 1350 fps and I'm only about 80-100 fps too slow.

Does anyone have any suggestions?

Now, let me share an experience I've had.

Last fall I worked up a load of 2.5 gr. Unique in .38 Special cases under a 205 gr. bullet. This was to be used in a .357 Maximum rifle for small game. It would group into 1-1.5 inches and about 2 inches low of point of aim at 50 yards (sights set for the full-throttle deer load). At 25 yards they were spot on. I could see using these for a wide variety of small game including ground hogs, fox and "others" of that size. I loaded 50 to have to use and tested part of that batch to make certain I had it right. All was well. However, I had never chronographed that load. I did use one round to take one squirrel (on the ground).

Well, today I took it with me when I went shooting the Max (testing Lil'Gun loads). VERY disappointing! What happened! Well today (temp 59 degrees, similar to when I worked up the load) velocities went from 83 fps (yes, not a typo) to 340 fps. Most were striking 2 feet low at 50 yards (but 3 were spot on! ). These loads were useless today.

About midway through the test it occurred to me that they had been stored bullet down in the box and maybe the powder was not next to the primer. All following rounds (18) were given a sharp (but safe) rap on the bench before firing and the rifle barrel was elevated immediately before firing. Little if any improvement. Indeed, I did get a good group, just 2 feet too low! The 3 that were right on were from the first 22 rounds...

I don't know what happened here but I'm going to try a few more and see what happens...

I've recently been working with the .357 Maximum and Lil'Gun. Loads shown at the Dan Wesson page show a max of 23 gr. with 180 gr. bullets and 21.5 gr. with 200 gr. cast bullets. My experimentation took me to these limits with the 180 gr. Hornady SSP and 200 gr. Hornady RN. However, there was a problem with "sticky" cases. IOW, pressures are too high. So I dropped a grain for each and the 200 gr. Hornady still does 1939 fps (excellent) for 1670 fpe, 24 fps AD and a 28 SD. The hotter charge was better in that regard but one does not want to be forced to aid in the extraction of cases. You should just pluck them from the chamber without the use of descriptive phrases!

With the 180 gr. SSP, I only dropped the charge by .5 gr. and in a repeat of the previous experiment, velocities did not change (increased slightly!) but also the AD and SD increased substantially. I'm going to drop this charge the other .5 gr. (as I should have done) and try again. If all goes as before, velocities will average just below 2100 fps and the AD and SD numbers will be similar to the load with the 200 gr. Hornady.

I think it is very interesting that I can beat FACTORY .35 Remington loads with this case. Still, there are limits to what you can do and reloads in the .35 Rem. will only do about 2000-2100 fps with loads safe in both my M8 Remington autoloader and the Contender carbine. However, I have pushed the 200 gr. Hornady RN to 2200+ fps in the Contender.

*********

I received the first 50 of 100 bullets from Stone Fence today. I think I'll be getting 100 new cases and loading them all with this bullet and 32 gr. of RL-7. That will probably do me with this cartridge for the rest of my days.