Load accuracy, 24" barrel to 18" suppressed.

No doubt this question's been asked and answered. Had a look could't find. Hence:

I have a Ruger M77 Mk1 7 x 57 with a 24" Shilen barrel. Three distinct loads group (3 shot) under MOA. The rifle doesn't see any action because it's parked next to a shorty suppressed .308.
Seriously considering chopping the 7x57 24" to 18" and suppressing. Question: Can I expect the loads developed with the 24" to perform simarlarly with the barrel shortened to 18", excepting velocity? Don't want to start from scratch and would love to start the rifle walking again.

Cheers

Chop down to 22'' try,if you don't like. Chop down to 20" if you don't like,then down to 18''.Easy to chop down,bloody hard to add on.

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Originally Posted by RugerM77

No doubt this question's been asked and answered. Had a look could't find. Hence:

I have a Ruger M77 Mk1 7 x 57 with a 24" Shilen barrel. Three distinct loads group (3 shot) under MOA. The rifle doesn't see any action because it's parked next to a shorty suppressed .308.
Seriously considering chopping the 7x57 24" to 18" and suppressing. Question: Can I expect the loads developed with the 24" to perform simarlarly with the barrel shortened to 18", excepting velocity? Don't want to start from scratch and would love to start the rifle walking again.

Cheers

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no because barrel harmonics are going to change.

Could be that the loads shoot better, same or worse.

Might be lucky, might be not.

You will only know once you have tried it, but i would expect to have to do another round of load development...

Another question: would shortening it to 18" (sacrificing quite a bit of speed) make you take it over the 308?

I think the options you have are the best of both worlds - shortening the 7x57 might make it useless with harmonics changes and lack of speed with the shortened barrel but you still have a handy .308 short rifle when needed.

If anything suppress the 7x57 so it takes the same can as the .308...

I find this with my hunting .308 - took it from 24" to 20" (didn't go shorter as I had an inkling I'd regret it). I am regretting going that short with it, as I'm finding that it just isn't generating the speed that the comparable but heavier barreled 20" version I have. The one I shortened is a 1-10", the heavy barrel is a 1-12" twist so you'd expect maybe a bit of difference but the 1-10" appears several hundred fps slower. Scratching head as to what to do now...

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Originally Posted by No.3

I think the options you have are the best of both worlds - shortening the 7x57 might make it useless with harmonics changes and lack of speed with the shortened barrel but you still have a handy .308 short rifle when needed.

If anything suppress the 7x57 so it takes the same can as the .308...

I find this with my hunting .308 -. Scratching head as to what to do now...

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simple answer...make it shorter still and for fook sake dont put it anywhere near chronograph...be happy its short and light and kills stuff under 200 yards no trouble at all.....if your in longer range country take the longer heavier one.

as to the OP......agree 100% put suppressor on 7x57 and leave it long. if you absolutely HAVE to shorten...do as trout said and do it in stages.

Greetings @RugerM77,
To me you now have two different rifles. If you change one to be like the other will you use it more or will you still favour one. If the answer is probably then why do it? Perhaps it would be worth considering a different use for the 7mm. A walking around only half pie hunting rifle. I am sure you have hunts like this. If you don't yet then you likely will given time. This is called rifle walking and we tend to do more of it as we get older at least that is my excuse.
Regards Grandpamac.

I wouldn't do it.









I'd cut it to 16".

Hack it off man shorts good not hard to tweak a load you’ll find their more sensitive to seating depth rather than harmonics anyway

Quote:

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Originally Posted by No.3

I think the options you have are the best of both worlds - shortening the 7x57 might make it useless with harmonics changes and lack of speed with the shortened barrel but you still have a handy .308 short rifle when needed.

If anything suppress the 7x57 so it takes the same can as the .308...

I find this with my hunting .308 - took it from 24" to 20" (didn't go shorter as I had an inkling I'd regret it). I am regretting going that short with it, as I'm finding that it just isn't generating the speed that the comparable but heavier barreled 20" version I have. The one I shortened is a 1-10", the heavy barrel is a 1-12" twist so you'd expect maybe a bit of difference but the 1-10" appears several hundred fps slower. Scratching head as to what to do now...

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Greetings,
I did read somewhere that hammer forged barrels often have a slight choke going toward the muzzle. Sometimes this can result in significant loss of velocity when the barrel is shortened. You would expect around 100 fps loss going from 24 to 20 inches but it sounds that you have had more than this. Of course I can't find the source now. I have been working with a .308 lately with a 24 inch barrel that consistently produces more velocity for both factory and handloads than the data would suggest A different .308 with a 20 inch barrel gives around 160 less fps and is more in line with the data after allowing for barrel length.
GPM.

Thanks for the feedback guys. Issues settled. 7x57 stays as it is. I will suppress it though. Hopefully the .308 can will do the job ok.
Cheers

the MDT team did some testing on barrel length

the speed was the main experience, but they find out that the grouping was moving through the process
so like STC said, the barrel harmonics will force you to redo all your reload testing

happy to hear, you wont cut a Shilen barrel lol

https://www.youtube.com/watch?v=XCqa2umL8ME