10MM 220gr Heavies... Anyone Messing With These?

H

huntinaz

New member
I'm about ready to start working up loads for the new Ruger GP100 10mm. I have the Lipsey's edition, 5.5" barrel. I have a supply of Rimrock 220gr cast. I'd like to get what I can out of them, Underwood and Buffalo Bore are getting 1200fps. Two powders I have on hand are 800x and Blue Dot. Longshot and Power Pistol and AA#9 appear to be the other popular choices for experimentation. I'm not opposed to buying them.

If you have done this, you know about the scarcity of data. Anyone else messed with these? Appreciate any related experience.
 
I'm interested in the same since I just got a Ruger GP100 MC 4". I found quite a bit of info on the 10mm auto but nothing so far for revolver. Being somewhat new to reloading I want to gather every piece of info available.
 
I wasn't even aware a 220 gr bullet was available in .40 . I checked my manuals and they only go up to the 200 gr. Per my Hornady manual they are pushing the 200 gr bullets to a max of 1150 fps. I'm loading 10mm but my ideal bullet is the 180 Armscor 180 fmj rnfp . 13.3 gr of AA#9 at 1236 fps is my best load. FPS data shot from my 1911 Kimber target II 6" bbl. I tried some 800X and that was a lousy , inconsistent power ! I started seeing over pressure excessive flattened primers at around 1330 fps with the 180's using 800X my velocities were all over the place with an extreme spread of about 100 fps.
 
I've been using SNS Casting's poly-coated 220gn HC FN boolits.

My go-to powders are AA7 & AA9. Seems I get better accuracy with the AA7 out of my 6.2" longslide G40, but that's my loads in my gun.

FYI, the poly-coating makes these FN slugs feed snot-slick up the ramp, and the coating keeps the factory tube from leading up. Easy and quick to clean too.
 
I have done some hard cast workups with the 180's and JHP's at 200 grains. Im not sure how long that bullet is but AA#9 is probably going to fill the case all the way up. I personally do not like 800x because I load 10mm on a dillon 650 so I don't hand weigh each charge. I use Longshot but AA#7 & Powerpistol will work too. As will blue dot.

My load with the 200 gr JHP's using longshot yields 1275 fps out of a 5.3" alpha wolf fully supported barrel in my G20, and about 1240 fps out of a Fully Supported Ruger SR1911 Target with ramped barrel (5").

It is a hot load but with fully supported chambers it is no problem. The 180 grain hard cast is my mild load averaging around 1200 fps out of both guns (+/- 20 fps).

1200 fps with a 220 gr hard cast should be no problem in a 5.5" barrel. Personally I would try the blue dot first and see how it performs and if you don't get what you want, try longshot. Hodgdon rates Longshot between AA#7 and AA#9. Blue Dot and AA#7 are right next to eachother so if Blue Dot doesn't work, I wouldn't bother with AA#7 either. Again, my concern with AA#9 is because it is slow, and does not compress worth a darn, that you will top out on case capacity before achieving your goal.....but then again maybe not.
 
I picked up a can of Longshot to try first. I may experiment with AA#9.

I have the luxury of seating the bullet longer in the revolver so that helps with case capacity and pressure
 
Cartridge is from Ammo Manufacture: Underwood 220gr Hard Cast
Ballistics Information: 10mm Auto
Muzzle Velocity: 1240 fps
Muzzle Energy: 750 ft. lbs
Brass Make/Headstamp: Underwood - Brass
Bullet Make/Weight/Construction/Info; Length 0.7310”/Dia. 0.4010”: 220gr. Hard Cast * * *
Click to expand...

That about what I'm getting out of my 6.2" Glock 40 with handloads using SNS Casting's 220gn poly-coated FN slugs.
 
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