CMMG 8.5" 300blk

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Abiqua
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Location: Oregon Territory

Re: CMMG 8.5" 300blk

Post by Abiqua »

A machine gun is not a rifle so it cannot be an SBR.
eastern_hunter
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Re: CMMG 8.5" 300blk

Post by eastern_hunter »

... chuckle ...

M16 is a shortie as registered ... but doesn't matter anyway.
dtom29
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Re: CMMG 8.5" 300blk

Post by dtom29 »

I went with the upper not just the barrel.
8.5 in. CMMG upper...
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flashmc
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Re: CMMG 8.5" 300blk

Post by flashmc »

Here is my pistol with an 8" CMMG 1:7 300BLK barrel. It runs perfectly, but I'm also still developing loads right now. I have my subsonics almost completely dialed in, need to test a few more loads, just bring the muzzle velocity up a bit. Then I will start developing my supersonic loads.

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jwb47
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Re: CMMG 8.5" 300blk

Post by jwb47 »

nice build I hope you enjoy it as much as I enjoy mine . you will find they shoot super-sonic pretty damn good .
bye the way there is no need for the suppressor wrap I can assure you that once is the only time you will grab a hot suppressor. I know a guy who done that :oops:
anotherkelley
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Re: CMMG 8.5" 300blk

Post by anotherkelley »

flashmc wrote:Here is my pistol with an 8" CMMG 1:7 300BLK barrel. It runs perfectly, but I'm also still developing loads right now. I have my subsonics almost completely dialed in, need to test a few more loads, just bring the muzzle velocity up a bit. Then I will start developing my supersonic loads.

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Who makes your buffer tube?
brian1570
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Re: CMMG 8.5" 300blk

Post by brian1570 »

did i read that these barrels come with a .110 gas port? was thinking of opening mine up just a hair. running all milspec moving internals and had a failure to lock(once). this was on gemtech 187 grn poly tip. also not sure if my barrel is 8 or 8.5.
jwb47
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Re: CMMG 8.5" 300blk

Post by jwb47 »

brian1570 wrote:did i read that these barrels come with a .110 gas port? was thinking of opening mine up just a hair. running all milspec moving internals and had a failure to lock(once). this was on gemtech 187 grn poly tip. also not sure if my barrel is 8 or 8.5.
I have shot gemtech in my 8.5 inch cmmg and yes it functioned but marginal at best . try a better quality ammo and see what happens . open up the gas port and you will start having trouble with super sonics being over gassed . for every action there is an equal and opposite reaction .
brian1570
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Re: CMMG 8.5" 300blk

Post by brian1570 »

jwb47 wrote:
brian1570 wrote:did i read that these barrels come with a .110 gas port? was thinking of opening mine up just a hair. running all milspec moving internals and had a failure to lock(once). this was on gemtech 187 grn poly tip. also not sure if my barrel is 8 or 8.5.
I have shot gemtech in my 8.5 inch cmmg and yes it functioned but marginal at best . try a better quality ammo and see what happens . open up the gas port and you will start having trouble with super sonics being over gassed . for every action there is an equal and opposite reaction .
ok cool. still need to play with ammo types so this might just be a one time thing.

also i noticed that there was a lot of un-burned powder. is this because of the gemtech stuff or are all subs dirty?
jwb47
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Re: CMMG 8.5" 300blk

Post by jwb47 »

My limited experience with gemtech says yes its dirty
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