Gunsmithing To cut or not to cut a gas gun barrel?

[Pen & Sword Life]

I got a question that I hope you guys might be able to advice on.

Is there a minimum distance to observe on gas guns from the end of the barrel to where the gas is tapered off, in order for the rifle to function properly?

I'm running a Savage MSR-10 in 308W. From the factory it is "born" with an adjustable gas block, the barrel is 18". I'm considering having the barrel length cut 4 inches. If I cut the barrel I'm not gonna run a suppresor on the rifle again but utilize a "blast forward" muzzle device.

If this idea is completely ill adviced, do let me know. Don't wanna risk botching up my rifle - Rather have two functioning long guns.

This project is dependant on whether I buy a Sabatti Tactical EVO US some time next year (have to try out that one first).
Attached are pictures of my current MDR-10 setup as well as two power point mock-ups future setups..... Yes, I'm a geek that way

 

[saddlerocker]

Are you pinning a long muzzle device?
It will be an SBR at 14"

Probably need to know the gas port size to know if it will function 4" shorter and the adjustable gas block wide open.
I would bet it has issues. But maybe its got a crazy oversized gas port to begin with

 

[Pen & Sword Life]

I'm Danish and we don't suffer SBR issues

Gasport issues was/is also a concern of mine. Will have to figure that out too.

 

[LeftyJason]

Might get better responses in Semi Automatic.

Semi-Automatic Rifles

Discussion related to semi-auto rifles, both 5.56, 7.62, and all calibers in between.

www.snipershide.com

Probably smart to say you're in Denmark in the post.

 

[saddlerocker]

Yeah im no expert in 7.62 AR10 style guns, but likely you would need a lighter recoil spring and maybe a lighter bolt carrier if possible, but even then it all depends on the port size for that specific model.
It will either be a very soft shooting gun that functions, or it will short stroke and not fully cycle the action.

 

[TonyTheTiger]

Chances are your 18" barrel has a rifle length gas system. The muzzle will be just ahead of the port, maybe an inch of dwell time if memory serves. That's highly unlikely to work. A 15" barrel is a much better bet.

 

[UpSideDown]

Check the length of the gas system on your rifle (Mid or Rifle or something unique) and report back with that info and we can offer better advice.

 

[Pen & Sword Life]

Check the length of the gas system on your rifle (Mid or Rifle or something unique) and report back with that info and we can offer better advice.

Gotcha, the front end of the gas block is at the 13" mark of the 18" barrel.

 

[Pen & Sword Life]

Yeah im no expert in 7.62 AR10 style guns, but likely you would need a lighter recoil spring and maybe a lighter bolt carrier if possible, but even then it all depends on the port size for that specific model.
It will either be a very soft shooting gun that functions, or it will short stroke and not fully cycle the action.

Oh, that sounds like it could/would represent a host of functionality issues if the barrel is cut to other lengths. Thank you for that reflection. The Savage MSR-10 has a lot of proprietary stuff going on and since they are no longer listed on their website, spareparts may be an issue if project idea is a bust.

 

[saddlerocker]

Gotcha, the front end of the gas block is at the 13" mark of the 18" barrel.

So if you wanted to cut the barrel to 14" you would cut right at the opposite side of the gas block? I dont think that'll work lol.

 

[Pen & Sword Life]

So if you wanted to cut the barrel to 14" you would cut right at the opposite side of the gas block? I dont think that'll work lol.

That's why I'm asking mate, I'm no gun smith, might as well ask before I approach a gunsmith in Denmark for any type of work. But given that I would likely need to get a different bolt as well as buffer spring, this idea seems to be dead in the water.

Still gonna buy a new bolt gun at some point in time though

 

[1911hombre]

Why did you think you wanted to cut it?

 

[saddlerocker]

Yeah, you need some distance between gas port and when bullet exits muzzle to cycle the action.

If you could trade for, or find a 16" barreled upper receiver group for that MSR-10, you could likely take an inch off that.
Or sell the whole 18" rifle and buy a 16" MSR-10 if possible.
It should have a shorter gas system to start with. (A mid length gas system ~9" instead of 13")

 

[TonyTheTiger]

Just took some quick measurements. A 14" rifle gas barrel would leave you about 1.1" of dwell time. I have one rifle with 2" dwell time and it's definitely as short as I would consider going.

 

[Zak Smith]

If it has midlength gas, it will probably still work at 14".

 

[TheOE800]

Just took some quick measurements. A 14" rifle gas barrel would leave you about 1.1" of dwell time. I have one rifle with 2" dwell time and it's definitely as short as I would consider going.

Muzzle end of gas block at 13” does sound like ~12” gas system doesn’t it? That would be ~2” of dwell.

 

[Pen & Sword Life]

Why did you think you wanted to cut it?

Can't legally own semi-auto 5.56 box magasine guns in Denmark and this would be my closest bet to have a shorty'ish gas gun. That or selling my MSR-10 and buy a DD 12,5" SBR 308W..... But I don't think I got the budget for that right now.

 

[Bcamos]

Might get better responses in Semi Automatic.

Semi-Automatic Rifles

Discussion related to semi-auto rifles, both 5.56, 7.62, and all calibers in between.

www.snipershide.com

Probably smart to say you're in Denmark in the post.

His location is irrelevant to the question.

 

[LeftyJason]

His location is irrelevant to the question.

Agreed but it would at least weed out the sbr responses and get to the meat of the question sooner.

 

[Pen & Sword Life]

Agreed but it would at least weed out the sbr responses and get to the meat of the question sooner.

Mate, check just above your original comment

 

[308pirate]

His location is irrelevant to the question.

It sure as fuck is, as it will weed out stupid answers like "you'll need a tax stamp" and "get a 223 instead"

 

[LeftyJason]

Mate, check just above your original comment

Not everybody reads all of the posts before responding especially the third post. I knew that before posting my comment.

I also suggested you ask this in Semi Auto instead of Armory (which you still haven't done). There are certain people that stay in different sections and don't always go into other sections. The people you want are in Semi auto. The reason why I suggested to have location is for when it goes to semi auto.

 

[Oldguy03]

Yes, to cycle the action, there must be some gap between the gas port and the point at which the bullet leaves the muzzle. It will most likely still function at 14" if it contains midlength gas.