10mm Hunting load for Barnes TAC-XP 140gr and Longshot in a G40

[Deernut]

That link is interesting because I don't have a feel for how high (fps) I can go so I am  proceeding cautiously, but it is time consuming and I have to order more expensive bullets.  I went with a 140gr over the 155gr specifically because I heard about the problems with case capacity.  I never did the math to see if 155gr bullet at 1500fps (out of a 6") is more killing energy than 140gr at 1600.  I'm operating on the premise that energy is mass x velocity squared so having velocity is more important.  If you can send a 155gr at 1500fps in safe SAAMI specs then I'm optimistic I'm on the right track and will max out at my next trip to the range with the 10.8, 11.0, 11.2, 11.4 I loaded last night.  Maybe I should make a 11.6 and 11.8.      

I wondered why the Buffalo Bore was only loaded to 1.238" COAL.  Why not 1.260" -- that functions perfectly in my G40 (Barnes TAC-XP 140gr).


Thanks, JIM

[Trapper6L]

plateau in velocity between 10-10.8gr

More than likely the plateau is due to the extra powder being blown, unburned out of the barrel, before it has a chance to fully ignite. Been there done that with H110 on another pistol. If you have the means, might try one round at night and look for a brilliant muzzle flash. I'll bet it's a dandy.

[Graybeard]

I'd have to agree with Trapper. If more powder isn't getting you more velocity, it's not all burning.

I've pushed some 155gr XTPs out of a 5" 1911 at a little over 1500fps with 800X. Primers were slightly flattened, but nothing too scary. Since you're chasing speed, that might be the way to go. Be careful if you choose this route. 800X meters like corn flakes and there have been reports, on other forums, of pressure spikes when reaching the upper limits.

Good luck with this. Keep us posted.

[Deernut]

Well, that's disappointing, but it does make sense. Night shooting a few rounds sounds like an Instagram-worthy endevour.  I'm on my second powder - I knew 800X was another option but I don't think I'll go there.  I'll see what my already-loaded 10.8, 11.0, 11.2 bring and then see what kind of accuracy I get from a few of the top loads.  If I could send a 155gr at 1500fps then there's no sense in shooting a 140gr the same velocity.  I'll wait before I buy more bullets.

Thanks, JIM

[Spudmeister]

I had a similar experience to Trapper with H-110 in 357 magnum.  It was a famous load with a hard cast 185gr bullet.  But I spent an entire summer trying to get that bullet over 1,200 fps in the 4" barrel with H-110.  The solution turned out to be one of two things.  I went to a faster burning powder (Blue Dot) and got an extremely accurate and easy to shoot  1200 fps load.  The other thing I did was seat to bullet deeper and gave it a heavy factory crimp.  Yes that jacked pressures but it also gave the H-110 powder the high pressure high resistance environment it needed and suddenly I had 1,325 fps in a max load. 

To a degree your going from Longshot to Power Pistol was like my going from H-110 to Blue Dot.  And if the Buffalo Bore shortened the cartridge with your Barnes bullet you can be sure it was not because the case is too big.  Maybe it was for feeding and maybe it was for better ignition.  Years ago I had some issues in rifles with Barnes bullets.  Finally got them worked out (they are good bullets) but they are different from any cup & core type bullet. 

I am thinking you'll benefit from any extra neck tension you can come up with.  You can shorten the LOA to the Barnes number, drop your charges and work up again.  It is possible your bullet is moving too early in the ignition process and not allowing pressure to build.  Maybe magnum primers would help but I have no experience there with such an easy to ignite powder as Power Pistol.  And finally, you may get better performance with an aftermarket barrel that has smaller internal dimensions. 

I am just thinking out loud about what it may be or what combination of things it may be.  Be careful, go back and work forward again slowly.  On the other hand, the Hornady 155gr XTP is an awesome bullet.

[Deernut]

I should have just bought 2 boxes of Buffalo Bore.....


The PowerPistol is inconsistent and plateau'ed.  It is a compressed load and probably burning a lot of the powder outside the muzzle.  I reached 11.4gr of PowerPistol and not getting much more velocity.  The graph is my data from the start showing the failure to get a linear relationship between more powder and more velocity (PowerPistol powder, 140gr Barnes TAC-XP, WLP primers, new Starline Brass, COAL 1.260, Crimped at 0.420.   Keep in mind the sample size is generally 1-3 rounds for each of these, but variability only increases with sample size. 

Still no pressure signs.

Here's powder, grains of powder, bullet, COAL, Primers, Velocity range, Vel. Ave., # rounds
PowerPistol   10.8   140   Barnes TAC-XP   1.26   WLP   1448-1518   1488      3   no pressure signs/ES 70.1 and SD 36.1/crimp .419-.420
PowerPistol   11   140   Barnes TAC-XP   1.26   WLP   1461-1500   1479      3   no pressure signs/ES 38.8 and SD 19.7/crimp .419-.420
PowerPistol   11.2   140   Barnes TAC-XP   1.26   WLP   1460-1519   1494      3   no pressure signs /ES=58.7, SD=30.6/all brass under 0.431/crimp .419-.420
PowerPistol   11.4   140   Barnes TAC-XP   1.26   WLP   1511                   1511      1   no pressure signs on primer, brass under 0.431/crimp .419-.420

I'm switching to 800X powder and Lehigh Xtreme Defense 150gr and starting over at the upper end of the published range.  If I can only get 1500fps then I want to send a 150gr bullet at that speed.

Thanks for all the help, I'll keep you posted as I pivot in a different direction.

Note these loads will probably blow your pistol up so start low and work up like I did.

JIM



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