As some of you know

Mark Conner
[subject]
Wednesday, January 19, 2022, 18:13 (827 days ago)

I enjoy shooting a few rock chucks in the Spring when time allows. In the past, I have always used either my Coyote Classic in 218 Mashburn Bee or 300 GNR in a rechambered 30 carbine. After picking up an older Contender frame, Gary built a 7 GNR barrel for me that I was able to use last season.

In the 7 as in the 218 and the 300 I wanted to shoot cast for the chucks. My BIL, who has a 7 TC/U, has a couple moulds he got from one of Gary's estate sales so I borrowed the Lyman 287346 from him and used it last year and it served me well.

But I really wanted a flat nosed hollow point design, so I contacted Al at NOE and after a 5 month wait (everybody is behind) a 4 cavity 288135 with h.p. pins showed up.

Bullets were cast and load testing began. I started with IMR 4064 and a good load was finally found but it was reduced enough that the powder became pretty position sensitive, I could get good groups but I had to raise the muzzle vertically then lower it slowly, without doing this the load shot vertical strings of 3" at 65 yards. Not wanting to do this each time I shot I figured I had a couple of options... (1) Switch powder (2) or try a filler.

I tried the switch powders first, going with 2400 an ok load was found, but not having much 2400 on hand and it just being an ok load I went to the other end of the scale and tried IMR 4350. It did not shoot any better than 4064 and I used a lot more of it and not getting any better groups it was not really worth it to me. So bring on the filler. I was very leery to try this with the stories of ringed barrels. I thought I understood the process so I went back to my 4064 load that shot so well with muzzle elevation and put .8 of a grain of dacron filling in the space between powder and bullet, not packing it tightly but making sure it was well on the powder and filling all the space in the case to the bullets base. The addition of the dacron really cleaned up the powder burn and made good consecutive groups, but ringing a barrel was always on my mind.

Today I decided to try some IMR 3031, I have a very good load with this powder and Nosler 120 gr. BT. I started with 2 grs. less than the 4064 load, expecting about the same results I was quite pleased when I walked up to the target and saw this, and I don't have to worry about the dreaded barrel ring.

About 65 yards, sitting on the cold wet ground shooting off cross sticks. I know if there is a better load I could not shoot it any better. My search for a cast bullet rock chuck load is finished.
[image]

Mark I am sizing those exact bullets fit my 7GNR

MTM
[subject]
Wednesday, January 19, 2022, 18:22 (827 days ago) @ Mark Conner

12” contender now. I’ll have to start with that load, and see if my barrel likes it as well. [image]
Well timed post, I’m half done gas checking.

Nice looking bullets.

Mark Conner
[subject]
Wednesday, January 19, 2022, 19:26 (827 days ago) @ MTM

let us know how they shoot.

Nice load

Paul lauer
[subject]
Wednesday, January 19, 2022, 18:26 (827 days ago) @ Mark Conner

Those should put up quite a spectacle when they make contact with a chuck. I have enjoyed seeing your pictures and reports on your remodeled 30 carbine. I have one on the safe that may get some similar treatment.

When the opportunity

Mark Conner
[subject]
Wednesday, January 19, 2022, 19:32 (827 days ago) @ Paul lauer

arises definitely go the 300 GNR route.

Great work! I was always shocked by Lyman

WB
[subject]
Wednesday, January 19, 2022, 18:58 (827 days ago) @ Mark Conner

using all these fast shotgun powders in their manual. I have tried AA1680 and Lil'gun in .25-35 with cast bullets and great results. I've not shot it in the .256 Falcon yet but you inspire me.

I wanted to go even slower

Mark Conner
[subject]
Wednesday, January 19, 2022, 19:41 (827 days ago) @ WB

with IMR 4831 but I see no sense in it now.

Of all things 4895 has been a good powerful cast bullet

WB
[subject]
Thursday, January 20, 2022, 09:23 (826 days ago) @ Mark Conner

powder for me. I was blasting some 350 gr. .375 RNGC out of the .378 GNR at near full power with no leading. The long cast RN riveted badly and tumbled in my backstop media but the speed was there.

In .416 Rigby I have done good work using the surplus .50 BMG powders and magnum primers. I have a 325 gr. and 375 gr. mould for it. I did it in .458 Win. too but seated long way into the throat like a .458 Lott to get enough powder capacity. The stuff burns like a candle!

Nice work!!

Jim Taylor
[subject]
Wednesday, January 19, 2022, 19:06 (827 days ago) @ Mark Conner

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Thanks Jim

Mark Conner
[subject]
Wednesday, January 19, 2022, 19:43 (827 days ago) @ Jim Taylor

that means a lot coming from you.

very good Mark!

Gary Reeder
[subject]
Thursday, January 20, 2022, 12:12 (826 days ago) @ Mark Conner

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Thank you

Mark Conner
[subject]
Friday, January 21, 2022, 19:14 (825 days ago) @ Gary Reeder

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