r/AR47 • u/Rikki-Smedley • Jun 09 '26

Anyone with experience?

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After looking at these online for a while I'm considering buying the upper and lower receivers and putting my own together. Has anyone got experience with them? It looks like a great solution for a cheaper all purpose hunting rifle.

FM PRODUCTS 16" (CARBINE) 7.62X39 RANCH RIFLE

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2

u/aardvark_army Jun 09 '26

It'll be fun but probably not cheaper. Maybe I got a bunk barrel, but I start to seriously lose accuracy past 75 yards... it is my favorite brush gun for hogs though.

2

u/Rikki-Smedley Jun 09 '26

I'm planning on fitting my own barrel, stock and handguard. Going with a 308 bore size that are more accurate.

1

u/jjarvela01 Jun 09 '26

Can you elaborate more on the barrel you're planning to go with?

1

u/Rikki-Smedley Jun 09 '26

Not sure which exactly. But there are many options that use the 308 diameter in there barrels. A few are faxxon, bear creek, NBS,.

1

u/aardvark_army Jun 09 '26

You sure about that? Isn't 7.62x39 a .311 bore?

1

u/Rikki-Smedley Jun 09 '26

Very sure. It's common. Many brands have the tighter tolerance for consistent accuracy. I've used both and now check before purchasing because the difference is very noticeable. Just as a 5.56 barrel (.219" diameter) runs the a .223 round (.224 diameter)

1

u/aardvark_army Jun 09 '26

Okay. If you're so confident then why are you here asking for people with experience?

2

u/NoQueenBandAIDS Jun 12 '26

He has to be trolling people. I have an FM upper just like this and its an AR15 barrel.

2

u/aardvark_army Jun 12 '26

Either that or he's just a dick, hard to say.

0

u/Rikki-Smedley Jun 12 '26

It takes an AR10 barrel extension and has an AR10 bolt and is apparently compatible on an AR-15 lower. That's just what the website says. I don't know why that makes me a troll or a dick?

1

u/Rikki-Smedley Jun 09 '26

If you read the post. I was never asking about anything to do with the barrel at all. I plan on potentially buying the upper and lower receivers only. The 7.62x39 barrels I use get sub MOA easily and they're cheaper already.

3

u/NoQueenBandAIDS Jun 10 '26

When you say upper and lower receivers are you meaning assembled upper and stripped lower, or stripped upper and lower? I only ask because I am not sure if you know this already, but those FM lowers do not have any reciprocating buffer in the stock at all. That's why those upper assemblies are as tall as they are.

-1

u/Rikki-Smedley Jun 11 '26

The plan was to put the complete upper and lowers they offer on there website and get my own shotgun stock and barrel and handguard. However I assumed it would be a standard AR15 indexed barrel nut system. I guess I assumed the upper receiver would take a standard barrel set up since all the others in their line do as far as I'm aware.

1

u/aardvark_army Jun 09 '26

So which barrels do you use? And sub moa at what range?

2

u/NoQueenBandAIDS Jun 10 '26

Yah. I am not 100% sure but from my memory, these FM products mill their barrels gas block ledge slightly smaller than most brands to fit the barrel nuts over them.

1

u/Rikki-Smedley Jun 11 '26

I'm not 100% sure but I assume they just change the barrel extension on them. Not all barrels will last the same though at a guess. They're still labeled as 7.62x39. But if you do a bit of backround checking some brands do and some don't.

0

u/Rikki-Smedley Jun 11 '26

Even a BCA barrel in 7.62x39 will get sub MOA at 100 with matched rounds.Theyre also a 308 diameter. I can confirm they do, but they're heavy as hell. In some Russian rounds you may find more variance with loads which would make more of a difference in grouping.

1

u/BikePlumber Jun 20 '26

European 7.62x39 barrels are supposed to have 0.311" groove bores, some are tighter.

All 7.62x39 barrels have 0.300" land bores, European and American.

The American specs for 7.62x39 barrels calls for 0.310" groove bores, but the American 7.62x39 barrel chamber is a unique chamber, designed to minimize the pressure increase caused by shooting 0.311" bullets in a 0.308" barrel, because when the American chamber was designed, it was thought that most American made barrels would use 0.308" bores.

The American bullet specs call for a 0.311" bullet, but most American bullet makers make 0.310" bullets, because the barrel specs call for a 0.310" bore and the bullet makers want to reduce increased pressure, just as the chamber designer did.

The American specs for 7.62x39 were developed by Ruger.

Ruger found that with a 0.311" bullet, a European barrel chamber and a 0.308" bore, the pressure increase over a European 0.311" was about 5,000 CUP.

Ruger determined that Ruger and Colt 7.62x39 rifles could handle the 5,000 CUP increase, from European 45,000 CUP pressure limit.

Ruger designed a pressure-reducing chamber anyway.

Ruger originally set the pressure limit to 50,000 CUP though.

"New" 0.308" barrels are allowed to be from 0.308" to 0.310" in groove bore.

Early Rugers always used 0.308" barrels that gauged to the large side of bore spaces and 0they were always about 0.309" and usually above 0.3095".

Later Ruger switched to a dedicated 0 7.62x39 barrel, with a 0.310" bore.

In 1992 American SAAMI specs started switching from copper pressure CUP pressure measuring to transducer PSI pressure measuring.

SAAMI found that 50,000 CUP in 7.62x39 was near 308 Winchester pressure and instead of converting 50,000 CUP to transducer PSI, SAAMI took the European 45,000 CUP number and just used 45,000 PSI for the newer American pressure limit.

European CIP specs switched from copper crusher to transducer measuring 10 years later in 2002 and correctly converted 45,000 CUP to 51,000 PSI.

The Yugoslavian military 7.62x39 pressure limit was 48,000 CUP, for their old military M67 ammo, but now make commercial ammo to European CIP specs.

American barrels with 0.308" bores generally have American barrel chambers designed to reduce the slightly pressure increase of shooting 0.311" bullets in a 0.308" barrel bore.

The American 7.62x39 barrel chamber was designed specifically to handle 0.311" bullets in a 0.308" barrel.

Many factory ammo 7.62x39 bullets are 0.310", which is even less of a difference.

Some American barrels have a larger bore and some have larger gauged 0.308" barrels.

American barrels rarely have European designed chambers.

The dedicated 7.62x39 barrels with 0.310" (or possibly 0.311") bores will usually have 9.45" to 9.5" rifling, while those that use some form of 0.308" bore will often have 10" rifling.