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Like to build a 7.62 x 45 Czech (but necked down to .308) with boxer primers in a mini-action with 2.43" COAL. Anyone run one of these? If so, what do you do for a continual brass supply?
Last edited by Riflehunter; 02/17/24.
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Sounds fun. Buffalo Arms is the only place I know of that carries it. It is made from reformed 220 Swift brass. You might consider the Barnes 308x1.5” or 308x1.75”. Another would be an improved .308x39 or 30BR pending bolt face… I have wanted to do the improved .308x39 but have not got around to it.
Semper Fi
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I have been looking at building a mini bolt rifle in a smaller capacity 30 caliber. I have settled on having a 30 BR built on a Kimber. Wanted the reduced powder charge for running a short barrel with a suppressor. Interested to hear more about what your goal is for your rifle here.
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I have been looking at building a mini bolt rifle in a smaller capacity 30 caliber. I have settled on having a 30 BR built on a Kimber. Wanted the reduced powder charge for running a short barrel with a suppressor. Interested to hear more about what your goal is for your rifle here. The goal is to run 150's at around 2400 fps with temp. stable powder (Varget or H4895) in an extra-short action 6lb rifle including scope with a 20 " barrel. Need the case to hold around 36 grains of powder with the 150 projectile. Neither the 7.62 x 39 case or the 6.8 SPC case necked up holds quite enough powder. 4 rounds in the internal hinged floorplate mag.
Last edited by Riflehunter; 02/18/24.
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Joined: Jun 2013
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I have been looking at building a mini bolt rifle in a smaller capacity 30 caliber. I have settled on having a 30 BR built on a Kimber. Wanted the reduced powder charge for running a short barrel with a suppressor. Interested to hear more about what your goal is for your rifle here. The goal is to run 150's at around 2400 fps with temp. stable powder (Varget or H4895) in an extra-short action 6lb rifle including scope with a 20 " barrel. Need the case to hold around 36 grains of powder with the 150 projectile. Neither the 7.62 x 39 case or the 6.8 SPC case necked up holds quite enough powder. 4 rounds in the internal hinged floorplate mag. The 30 REM AR would do all the above but you might have 3 down in the mag. There is still enough ammo and/or brass out there to keep it running. It’s a dandy little cartridge.
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I have been looking at building a mini bolt rifle in a smaller capacity 30 caliber. I have settled on having a 30 BR built on a Kimber. Wanted the reduced powder charge for running a short barrel with a suppressor. Interested to hear more about what your goal is for your rifle here. The goal is to run 150's at around 2400 fps with temp. stable powder (Varget or H4895) in an extra-short action 6lb rifle including scope with a 20 " barrel. Need the case to hold around 36 grains of powder with the 150 projectile. Neither the 7.62 x 39 case or the 6.8 SPC case necked up holds quite enough powder. 4 rounds in the internal hinged floorplate mag. The 30 REM AR would do all the above but you might have 3 down in the mag. There is still enough ammo and/or brass out there to keep it running. It’s a dandy little cartridge. 4 in mag is absolute minimum. 5 would be better. Design of 7.62 x 45 Czech is about perfect for what I want, after necking down to .308.
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in a zastava the action opening is 2.29 the mag box is 2.35 . with 6.5G or 7.62x39 you can get 4 down and chamber over the 4th for 5.
I have a 7mm BR which was a 22-250 before. only 3 down and chamber one more.
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Vol of water in cc
7.62x45 ==2.79 30 BR === 2.66 7mm BR = 2.56 7.62x39 == 2.30
Out of a 22" bbl 2400fps I can see.
7.62x45 = Sierra 150sp OAL is 2.36.
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I'd probably go Howa over Zastava or CZ. more bottom metal options too.
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It’s an interesting round. Biggest issue I had with the Russian case head rounds was settling on an action that did all I wanted with the right size bolt face.
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I would NOT open a Zastava to a 284 (30rem AR) bolt face.
rim diam. and OAL
6.8 ==========.422=l==2.26 7.62r/grendel==== . 439===2.26 7.62x45======= .445===2.36
308 case =======.473
30 rem AR======.492===2.26
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At 2400 fps and using 150 Speer BTSP, scope set at 2.8" high at 100 yds, zero at 200 yds, 4.5" down at 250 yds... for those interested. Rated at maximum 62,366 psi.
Last edited by Riflehunter; 02/18/24.
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It does fill a niche above x39 cartridge but smaller than 308 size.
Did you find a mini rifle that fits?
Brass is formed from 220 swift?
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It does fill a niche above x39 cartridge but smaller than 308 size.
Did you find a mini rifle that fits?
Brass is formed from 220 swift? You use a Howa mini action and swap out the plastic for an internal mag and hinged floorplate so you get COAL of 2.43". That will also give you the 6lb weight including scope. Put on a stainless 12 twist .308 barrel at 20" at .600" at muzzle so it balances right and to make weight limit. The case capacity is needed so you can switch from H322 powder to the slower burning H4895 or Varget which needs around 34-36 grains to get reasonable velocity with 150's with temp. stable powder. I have over 300 Swift cases, but would prefer to buy 1000 cases if possible, hence the post. 150's or 140's (but virtually none made) are needed to get complete penetration through the shoulder with their better sectional density, and the .308 hole gives a bigger hole on lung shots for any tracking and faster kills even with negligible expansion if using a hard projectile for mainly the shoulder. The bigger .308 bore gives a bit more velocity for the same weight bullet. A lot less recoil than a .308 and less blast.
Last edited by Riflehunter; 02/19/24.
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Which bullet are you looking at using? I’m planning my build around the 110 and 120 gr TAC-TSX Barnes bullets. I have seen those bullets work well enough that I have faith in them.
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I'll start off with the 150 Speer flat base Spitzer HotCors or 150 BTSP (inexpensive). All copper at lower weight should also work...I don't have experience with the 110 and 120 TAC-TSX. I know that the 110 TSX is magnificent in the 6.8 SPC on hogs.
Last edited by Riflehunter; 02/19/24.
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The .30 cal 110 and 120 tac-tsx are designed for 300 blackout velocities. I used the 110 loads through a 9” sbr for a while on hogs. Bullet opens up quickly at those velocities while sticking together enough to penetrate. My experience was that a hit anywhere on a pig was enough to pin him in place long enough for a follow up shot. A hit in the mid section would put a basketball sized collection of guts out the exit wound.
My original plan was to try to build a 300 blackout or a 30 Ham’r. However, getting the characteristics I desired in an action built for a 223 case head was proving to be difficult. The 30 BR let’s me use the 308 casehead while still putting me in the right velocity window with 29 or 30 grains of H4198.
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The .30 cal 110 and 120 tac-tsx are designed for 300 blackout velocities. I used the 110 loads through a 9” sbr for a while on hogs. Bullet opens up quickly at those velocities while sticking together enough to penetrate. My experience was that a hit anywhere on a pig was enough to pin him in place long enough for a follow up shot. A hit in the mid section would put a basketball sized collection of guts out the exit wound.
My original plan was to try to build a 300 blackout or a 30 Ham’r. However, getting the characteristics I desired in an action built for a 223 case head was proving to be difficult. The 30 BR let’s me use the 308 casehead while still putting me in the right velocity window with 29 or 30 grains of H4198. What action?
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I wanted stainless, CRF, and 3 position safety in as trim a package as possible. So I had picked up a Kimber hunter on a trade and while messing with it I realized it gave me most of what I was looking for for this project.
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I have been looking at building a mini bolt rifle in a smaller capacity 30 caliber. I have settled on having a 30 BR built on a Kimber. Wanted the reduced powder charge for running a short barrel with a suppressor. Interested to hear more about what your goal is for your rifle here. I've also thought about the 30 BR on a Hunter! The factory 308 barrel should be able to be set back, to minimize expense. I've tried feeding of BR cases in the Hunter magazine, and they worked slick. So the Kimber Hunter seems like a good candidate for just what you're looking to do.
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