Twist for .32-20 (.308 bore) MGM barrel.

[upnorthwis]

I'd like to put a 24" MGM barrel with their .32-20 (.308 bore) on a Contender. I presently have a 10" TC .30-20 that out of the eight .30 cal. molds I own, only the 115 gr. will shoot with any accuracy. After doing some research, I find that the TC barrels have been made in 10, 12, and 14" twist. Almost assumed that mine would have been a 14" twist due to the only bullet worth shooting was the 115 gr. But no, after doing the tight patch routine, it's clearly a 10" twist which defies Greenhill and the twist chart on the MGM website. (In MGM's defense it is TC's barrel and not MGM's) I would like to shoot this rifle at 200 yds. with at least a 160 gr. cast boolit. So does anyone have any real world experience with the MGM .32-20 with 160 gr. or larger cast?

[Aunegl]

I used to shoot handgun metallic silhouettes. The TC 32-20 10" was my field pistol and big bore class gun. RCBS 165 sil and 200 sil can reach out and knock down 200m rams.

[upnorthwis]

I used to shoot handgun metallic silhouettes. The TC 32-20 10" was my field pistol and big bore class gun. RCBS 165 sil and 200 sil can reach out and knock down 200m rams.

J-word would shoot all day long, but I could not get a big (160 gr.) cast bullet to work in my 10" .30-20TC. The match I'm going to is cast only. S.E.Wis, used to shoot there once in a while. That's near Holy Hill isn't it?

[Larry Gibson]

14" twist will do nicely in a 24" barrel.

[upnorthwis]

14" twist will do nicely in a 24" barrel.

And that's with the 160 gr.?

[rockrat]

I shot the 165 sil in IHMSA also, but in an MOA w/14" bbl in 30-20, using a 1-10" twist. Used a healthy dose of WW680

[Kylongrifle32]

I have a 15" 30-20 MGM barrel ( not sure of the twist at this time) that I want to be just a cast Boolit shooter for cheap 100 yard plinking. Tried all the light boolits from 93 grains up. All have be sized to .309 dia. Haven't tried sizing to .311 yet. The best Boolit that has shown promise in my barrel so far is the Lee 309-150 FN. I started out shooting this Boolit with out a gas check with poor results for my liking. Did not want the added expense of gas checks ( wanted a round as cheap as a rimfires as far as plinking with). Went ahead and gas checked some and did some more bench test shrunk the group's down to 1 1/2" checked vs 2 1/2" w/ o checks. I then sent this mold to a cousin of mine that works as an apprentice in a machine shop. I had him bore the top of the mold to remove the taper for the gas check. This modification dropped the group's down to around 1" MOA.

As a side note this barrel will shot any 125- 130 grain jacketed bullet I have feed thru it into a clover leaf group at 75 yards all day long.

If you would like I can give you some of these modified boolits to try. They don't look the prettiest but they show some potential. I also did this modification to a Lee 309-120 RN mold but have not tried them yet. Other new calibers have taken me away from the 30-20 for now.

Mike

[Larry Gibson]

And that's with the 160 gr.?

I shoot 155 - 180 gr cast at sub-sonic velocities with excellent accuracy out of my 14" twist .308W rifle. Unless your 160 gr cast bullet is longer than the MP 180 gr cast [ 1.03"] then they should stabilize well in a 14" twist 24" barrel at reasonable velocity.

[upnorthwis]

Kylongrifle32: Machining off taper for GC. Thanks for the reminder because the match I'm going to is also PB.
Larry: 14 twist it is.
All others: Feel free to chime in.

Thanks all

[megasupermagnum]

I've been able to get a 150 grain to work in a 327 federal revolver with outstanding results. A 167 grain was so-so, although at only 1100 fps or so. That is a 1:16" twist. There is no reason your 32-20 wont work with a 160 grain with a 1:10 twist. I would try a different style bullet.

[Aunegl]

J-word would shoot all day long, but I could not get a big (160 gr.) cast bullet to work in my 10" .30-20TC. The match I'm going to is cast only. S.E.Wis, used to shoot there once in a while. That's near Holy Hill isn't it?

Yep, east on hwy 167. My overall cartridge length for the 32-20 was 2" with the brass trimmed to 1.28" and the diameter at .309". The powder of choice was A1680.