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

Pen & Sword Life

25 years army, now a happy civilian
Minuteman
Jul 16, 2021
48
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Denmark
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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 :)
 

Attachments

  • 1 MSR-10 18'' Denmark.jpg
    1 MSR-10 18'' Denmark.jpg
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  • 2 SAVAGE MSR10 14” (CUT BARREL) - BATTLE AND DRIVE RIFLE.jpg
    2 SAVAGE MSR10 14” (CUT BARREL) - BATTLE AND DRIVE RIFLE.jpg
    86.3 KB · Views: 76
  • 3 SABATTI TACTICAL MRR DELUXE-EVO US 22” + SPUHR QDP-4016 + ATHLON ARES ETR UHD 4.5-30×56 APRS...jpg
    3 SABATTI TACTICAL MRR DELUXE-EVO US 22” + SPUHR QDP-4016 + ATHLON ARES ETR UHD 4.5-30×56 APRS...jpg
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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
 
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.
 
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.
 
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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.
 
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.
 
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 :cool:
 
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")
 
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.
 
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.