10mm Longshot & Montana Gold Questions

[Blue Jacket]

I recently picked up a Glock 20 and just finished finding some 10mm brass. I have a couple of pounds of Longshot leftover from when I had a 28ga shotgun. I was going to load the 10mm with it. Hodgdon, with a 18o gr Sierra JHC bullet lists the min as 8.5 and max 9.5.

I have the following questions.

1) I was thinking of splitting it down the middle an go with 9 grains to start? Does anyone have any thoughts or a load they have success with using Longshot in a 10mm?

2) How much crimp? I set my lee crimp die for medium crimp given I expect more recoil from the round. I loaded a dummy round about a half dozen times with no setback.

3) Hodgdon lists the COL as 1.26 with 180 gr bullet. With the Montana Gold it looks like the bullet is seated deeper then I expected, could be I am used to looking at long loaded 40s for my STI. Does 1.26 with a 180gr MG sound right?

This round looks awesome. Can't wait to go put some though it.

Thanks for the assistance

[Ronnie j]

I've run 8.0 under a 180 zero in .40 1.125 long runs about 1200 fps out of a Schumann 5" barrel

[notfast]

9.3 GR @ 1.255 with a Zero 180 JHP and Wolf LP primer gave me 1233 f/s through the OEM GEN 3 G20 barrel. LO of 1217 f/s with a HI of 1251 f/s with a 10 shot sample.

No obvious brass bulge at feed ramp area. Primers still well rounded.

I could see a very, very slight brass bulge in the feed ramp area because I looked for it. Brass had been loaded twice before. Brass was a mix of PMC, WIN, and Double Tap (Starline???).

I have read that the standard internet 10MM Longshot load is, 9.2 GR of Longshot with any jacketed 180 GR bullet at 1.260 OAL will give around 1250 f/s.

9.0 GR should be a safe starting point.

Or, start at 8.5 and load a few, 8.7 load a few, 9.0 load a few and see what you think.

A chronograph is really handy if you don't have one.

Crimp: Just remove the bell. Neck tension should prevent bullet setback if the brass is good and properly resized.

Just for fun, I shot the 1233 f/s (222 PF) load at a practice match. One time. Total round count is usually 70-90 rounds. The matches are at night and the 10MM was about as loud as an open gun and a flamethrower.

I normally shoot the G20 with a 10MM-40SW conversion barrel, with practice night loads averaging right at 165 PF. It was quite a handfull compared to the 40SW loads. Shooting a 165PF 40SW afterwards felt like a 9MM subminor load.

[Blue Jacket]

Thanks for the info. I think I will start at 9 and see how it goes. I will back the crimp off a tad as well. No crono right now pthough maybe it's time to get one.

Edited January 23, 2014 by Blue Jacket

[tsp45acp]

No experience with any fmj/jhp bullets in 10mm. What I have loaded so far (my hot load) is a Penn 180g fpl, 8.8gr of LongShot at 1.250oal. Max load listed in 2 manuals was 9.2 & 9.3. Shoots great. No bulges in used brass, but enough power to let you know you're shooting a 10MM.

[G29SF]

I load 180gr Hornady JFP, with 9.5gr of Longshot. Never an issue. These are my "good" practice loads. I also load 200gr Hornady XTPs with the same 9.5gr of Longshot. (I use the same powder drop, without adjustment, for both loads.) The 200gr XTPs are my "awesome" loads.

Sent from my RM-820_nam_att_100 using Board Express

[G29SF]

I should add, for 180gr bullets, your listed range of grains of powder you are safe.

Sent from my RM-820_nam_att_100 using Board Express

[noylj]

>1) I was thinking of splitting it down the middle an go with 9 grains to start?

Back when I started to reload in about 1973, I twice found a "starting" load in my gun to be max or over max. As such, I ALWAYS start at the lowest starting load I can find and work up. Don't your manuals also state to always start with the starting load, or do you know better?

Here is my compilation:

Bullet Weight Powder Weight Velocity Note P.F. COL

HP-XTP, HAP, FMJ-FP 180 Longshot 6.4 950 Start 171

HP-XTP, HAP, FMJ-FP 180 Longshot 8.2 1150 Max 207

Sie JHC 180 Longshot 8.5 1221 Start 220 1.260

Hdy FMJ 180 Longshot 8.5 1239 223 1.260

Sie JHC 180 Longshot 8.5 1221 220 1.260

PD FMJ-FN 180 Longshot 8.8 1213 218 1.260

PD FMJ-FN 180 Longshot 9.1 1236 222 1.260

PD FMJ-FN 180 Longshot 9.4 1283 231 1.260

Sie JHC 180 Longshot 9.5 1287 Max 232 1.260

Based on this, 9.0gn is over max from at least one source--and that one does have a low velocity but it still produced max pressure. 9.0gn may be perfectly safe in your gun, but it is your gun and hands that may object to your assumptions.

You can not crimp the case enough to hold the bullet without destroying the case and bullet. All you need is the same crimp as any other semi-auto. It the the case/bullet tension that holds the bullet (do a finger pressure test to attemp to push the bullet into the case to detect bullet set back). All you need to do is remove the case mouth flare.

COL from any manual is what they used in their gun with its chamber and is usually quite a bit shorter than optimum. Find out how far you can seat the bullet and still have the round chamber. Learn how to work up your own COL.

Edited February 23, 2014 by noylj