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308 barrel conversion to 30-06

05 May 2022
@ 10:22 am (GMT)

David Kopp

I could help myself for purchasing a unused sps 308 26" barrel with a 1-12 twist. Here are my thoughts:

1 - replace my current 20" 1-10 in time with this barrel cut down to 22"

2 - re-chamber for the 30-06 or AI and lose some length but have a hb 30-06

I understand most of the variables with re-chambering. The long action i have for it is 1980's rem action. Is this worth even thinking about ?
Or keep in the wings for the 308?

Any thoughts would be helpful. I'm not rushing this project.



06 May 2022
@ 03:18 am (GMT)

Scott Struif

Re: 308 barrel conversion to 30-06
Hi David. Here’s an article that will give you a rough estimate of the velocity of the 308 at various barrel lengths:

Also, watch this video of Nathan’s. Towards the end he talks about having used heavy 308 bullets, up to 220 grain, without issue in 1 in 12 twist barrel.
06 May 2022
@ 03:36 pm (GMT)

David Kopp

Re: 308 barrel conversion to 30-06
Hi Scott, Thanks for the input. Im not really concerned abut barrel length for the 308 i understand and agree with Nathan about length. I have watch all of Nathan's videos. His knowledge is very consumable and I'm still re-reading and learning his teaching from the books and whomever in these discussions.

My main reason for posting was for the idea on changing the 308 barrel to a
30-06. Does this makes sense to alter a barrel that really does not need altering or buy a barrel blank and start from there.

In my mind I was thinking this was saving some steps/money. I would hope to achieve a barrel that is longer than 24" and be a heavy barrel 30-06. If it shot the heavy bullets, great, if not oh well. The 150-180 grain pills will fit most of the needs. [b]
07 May 2022
@ 08:42 am (GMT)

Nathan Foster

Re: 308 barrel conversion to 30-06
Hi David, really hard to answer this as each person has personal inclinations etc. if you want to, you could set up the SPS .308 as a hack so that you are up and running, then set about rebuilding your long action with a long 10 or perhaps even 9 twist .30-06 barrel, neither too heavy or too light.

Yes, 12 twist can work with heavy bullets. But try to keep my comments in perspective. Many people say that a 12 twist simply cannot stabilize a heavy bullet. The way this comes across, it sounds like the 12 twist is akin to a Mosin rifle, recovered during field plowing, no rifling, bullets tumbling, flying everywhere. "Duck everyone, that guy has a 12 twist .308". A load of fkn nonsense. A 12 twist can indeed (but not always) prove quite acceptable for mountain hunting using a heavy pill. On the other hand, the slow twist can reduce BC's. So depending on how far you want to reach and how much math you are willing to do (correcting the BC inputs), the 12 twist may or may not be suitable. I would not go out of my way to build a .30-06 on a 12 twist. But if and when I have a 12 twist .308 in hand, I will generally test shoot it with heavy pills to see what it can deliver.

07 May 2022
@ 12:26 pm (GMT)

Scott Struif

Re: 308 barrel conversion to 30-06
Interesting stuff . . . that slower twist adversely affects BC. It’s also true that faster MV reduces the need for faster twist. David has no immediate need to replace the barrel on his 308, yet wants a long barreled 30-06 now. He’s not particularly interested in shooting bullets heavier than 180 gr. He has a long Remington action lying around, and wants to save money. Seems like reaming the sps barrel to 30-06 makes sense for him.
09 May 2022
@ 02:28 pm (GMT)

David Kopp

Re: 308 barrel conversion to 30-06
Thanks Nathan, I must say I think I've been over thinking this and yes I am better off buying a 1-10 twist barrel blank than reshaping a pre-made barrel that may serve me down the road for my 308. My "try and save money idea" would bite me in the end.

The 308 I own is basically a replica to what you use with a factory 1-10 20" barrel that spits 168gr bullet out very well, again I was thinking a 1-12 twist had better fineness, crazy me. Now I understand why the 1-12 twist is 26" long. I guess if I want to muck around with 125-155grain bullets the 26" barrel would be an option if I got a smith to swap them out. For now the barrel will just sit at the ready.

As for the remington 30-06 I will see how the 195gr with superformance powder works out. The barrel is just the std 22" with a longer throat that the 195 and 208 gr bullets seat well. And will into look into getting a B+C long range sporter stock.

I am re-seeing using the 308 with the 165-168 grain bullets for anything below canadian mule deer size and 30-06 180-208 grain for elk or maybe moose.

Thanks again

Hi Scott, it's not that I wouldn't shoot the heavier bullets, I guess I was trying to justify getting the heavy barrel. I understand Nathan books and what he is saying. I sometimes over think and forget what has work for many people on this forum. For now I will look into what barrels are available here canada, and shoot what I have.



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