What the hey kinda AR did I buy?

[peter2772000]

I posted awhile back that I'd bought a Stag Arms 11.5" AR-15. I'd posted a pic, at which point one member stated that he doubted that the upper was a Stag Arms, due to the fixed handle. So I took a closer look at the sucker....

The lower is definitely a Stag Arms. The barrel, on the other hand, is an ATRS 5.56 NATO 1:10.
I can't find any markings on the upper. Where would the ID be located, exactly?

As well, is a 1:10 twist compatible with the 500 rds of 55 grain FMJ I just purchased? Did I get screwed?

 

[Onagoth]

I posted awhile back that I'd bought a Stag Arms 11.5" AR-15. I'd posted a pic, at which point one member stated that he doubted that the upper was a Stag Arms, due to the fixed handle. So I took a closer look at the sucker....

The lower is definitely a Stag Arms. The barrel, on the other hand, is an ATRS 5.56 NATO 1:10.
I can't find any markings on the upper. Where would the ID be located, exactly?

As well, is a 1:10 twist compatible with the 500 rds of 55 grain FMJ I just purchased? Did I get screwed?

The upper receiver marking might be as simple as an icon. Usually rearward of the case deflector just before the flatop. Different icon's will mean different things. Ie, mine has a keyhole, which means its a Cerro Forge upper.

Generally, faster barrel twists will be better able to stabalize the light bullets, so 1:10 should work just fine for those 55 grs. If not, let me know, I'll give you $50 for the lot

Heavier bullets above say 70 grains may not shoot as well out of a 1:10 twist...

 

[Ganderite]

"Generally, faster barrel twists will be better able to stabalize the light bullets, so 1:10 should work just fine for those 55 grs. "

I think you meant the faster twist will better stabalize heaver bullets.

I agree, the 1:10 should be dandy with 55. Should do 62 as well.

 

[Onagoth]

"Generally, faster barrel twists will be better able to stabalize the light bullets, so 1:10 should work just fine for those 55 grs. "

I think you meant the faster twist will better stabalize heaver bullets.

I agree, the 1:10 should be dandy with 55. Should do 62 as well.

Yes, I misspoke.

What I meant was higher ratio twists are geared for lighter bullets. So, basically want a 1:7 for the heavier 90 gr bullets.

 

[peter2772000]

I'm relieved to see that the 1:10 twist isn't going to be an issue for up to/including 62 gr.

For id, all I can find is a "P" and slightly lower and to the right an "M". These letters are right below the threaded sight of the handle (the screw of which has been butchered beyond belief, btw). Anything?

As well, I can't find any markings on the bolt either. I do know that the adjustable stock is a Rock River Arms.

I paid $950 shipped for this rifle. What do you guys think?

 

[Antoine22]

I posted awhile back that I'd bought a Stag Arms 11.5" AR-15. I'd posted a pic, at which point one member stated that he doubted that the upper was a Stag Arms, due to the fixed handle. So I took a closer look at the sucker....

The lower is definitely a Stag Arms. The barrel, on the other hand, is an ATRS 5.56 NATO 1:10.
I can't find any markings on the upper. Where would the ID be located, exactly?

As well, is a 1:10 twist compatible with the 500 rds of 55 grain FMJ I just purchased? Did I get screwed?

Non, ça s'appelle un achat impulsif.

 

[badboybeeson]

I'm relieved to see that the 1:10 twist isn't going to be an issue for up to/including 62 gr.

For id, all I can find is a "P" and slightly lower and to the right an "M". These letters are right below the threaded sight of the handle (the screw of which has been butchered beyond belief, btw). Anything?

As well, I can't find any markings on the bolt either. I do know that the adjustable stock is a Rock River Arms.

I paid $950 shipped for this rifle. What do you guys think?

you got a great deal!
bbb

 

[greentips]

1/10 will stablize up to 69gr.

 

[Hadrian]

If you paid $950 for a complete AR, you didn't get ripped of - that's for sure

 

[Plink]

I'm relieved to see that the 1:10 twist isn't going to be an issue for up to/including 62 gr.

For id, all I can find is a "P" and slightly lower and to the right an "M". These letters are right below the threaded sight of the handle (the screw of which has been butchered beyond belief, btw). Anything?

As well, I can't find any markings on the bolt either. I do know that the adjustable stock is a Rock River Arms.

I paid $950 shipped for this rifle. What do you guys think?

You got a bad deal.. tsk tsk.......

I'll give you $800 for it..


Now, are you going to come shoot some CQB??

 

[easy]

If the PM markings look like the ones in the following photo on the right side of your upper receiver, they mean the receiver was forged by Capco/Martin Marietta.

Colt used this forge to produce their early M16 upper receivers.

Your upper receiver is likely a Colt, but Capco/Martin Marietta may have forged that receiver for another manufacturer as well.

If you're interested in a list of other forge marking that appear on AR15/M16 upper receivers, let me know and I'll look though my library and list them here at a later time.

Also, check the style of the # 3 on the sight adjustment wheel on your receiver and let me know if it is the same style as you see in the photo. If it is, your receiver would be a Colt and that little wheel is a rare find these days.

I think you got a better deal than you realize.

 

[OZZ]

I posted awhile back that I'd bought a Stag Arms 11.5" AR-15. I'd posted a pic, at which point one member stated that he doubted that the upper was a Stag Arms, due to the fixed handle. So I took a closer look at the sucker....

The lower is definitely a Stag Arms. The barrel, on the other hand, is an ATRS 5.56 NATO 1:10.
I can't find any markings on the upper. Where would the ID be located, exactly?

As well, is a 1:10 twist compatible with the 500 rds of 55 grain FMJ I just purchased? Did I get screwed?

Its definately not all factory Stag but quality none the less. ATRS would be Alberta Tactical Rifle Supply, ya you`ve heard of him in the dealer section

 

[easy]

... The lower is definitely a Stag Arms. The barrel, on the other hand, is an ATRS 5.56 NATO 1:10.
I can't find any markings on the upper. Where would the ID be located, exactly?

As well, is a 1:10 twist compatible with the 500 rds of 55 grain FMJ I just purchased? Did I get screwed?

Indeed, a faster twist is desirable for a heavier bullet. -- Meaning the second twist number would be a lower number.

A fast twist barrel would be inaccurate with lighter bullets because such a barrel would overspin lighter bullets and compromise their gyroscopic stability. Thin jacketed varmint rounds being lighter and at a higher spin can break apart from high centrifugal forces during their spin, (read 300,000 rpm or so). Meaning the bullet's jacket will separate from the core.

.223 bullets which weigh between 35 and 50 grains, a 1:12 or 1:14 twist is most desirable. 1:9 being a common twist in AR rifles for lighter bullets, your 1:10 is a good moderate twist that will stabilize .223 bullets from 45 to 70 grain. So your 55 FMJs will do nicely out of your 1:10 ATRS barrel.

Heavier 5.56 bullets between 70 and 90 grains, would need a 1:7, or a 1:8 twist barrel to stabilize them reliably and deliver good accuracy.

I've been shooting 62 grain surplus C77s out of a 1:9 twist with good results. Now, if I was a better shot ... I would say 'exceptional' results.

If you're interested, there's a formula that can be used to calculate the ideal bullet spin and barrel twist to stabilize a bullet.

Let me know if you'd like me to decipher this formula for you so you can plug in your own numbers.

 

[peter2772000]

You got a bad deal.. tsk tsk.......

I'll give you $800 for it..


Now, are you going to come shoot some CQB??

It's stuff like that which limits your circle of friends to a grand total of one or two....


I dunno, I might try a CQB. You think there's any chance of my having a heart attack trying to lug my ole carcass around the course?

If the PM markings look like the ones in the following photo on the right side of your upper receiver, they mean the receiver was forged by Capco/Martin Marietta.

Colt used this forge to produce their early M16 upper receivers.

Your upper receiver is likely a Colt, but Capco/Martin Marietta may have forged that receiver for another manufacturer as well.

...Also, check the style of the # 3 on the sight adjustment wheel on your receiver and let me know if it is the same style as you see in the photo. If it is, your receiver would be a Colt and that little wheel is a rare find these days.

I think you got a better deal than you realize.

Thank you so much for the pics and explanations, that's exactly what I have with the placement of the Letters. And the #3 seems identical to the one in your pic.
I'm relieved that the upper isn't a Norc. I have nothing against Norcs, but that wasn't what I was buying...

Its definately not all factory Stag but quality none the less. ATRS would be Alberta Tactical Rifle Supply, ya you`ve heard of him in the dealer section

Nope never heard of 'em but had figured out that ATRS was Alberta Tactical. If you guys say that ATRS is reputed, then I'm happy.

1/10 will stablize up to 69gr.

Thank you.



Took it out to the range along with my newly-acquired SA CQB and the AR ran flawlessly. Funny though, the rear sight was adjusted to the far right. When the sighting in was completed, the sight was at the absolute far left in order to be able to group bullseye @ 50 yds. Strange...

Thanks to all for your input & information, it is appreciated.

 

[easy]

It's stuff like that which limits your circle of friends to a grand total of one or two....

I'm sure Plink was joking with that post and probably boozing it up at the hour he posted.

... Funny though, the rear sight was adjusted to the far right. When the sighting in was completed, the sight was at the absolute far left in order to be able to group bullseye @ 50 yds. Strange...

I wouldn't be too concerned where the rear sight aperture ended up provided you were able to zero it precisely on target. That upper was intended for a 20" barrel sight radius and your now 11.5" barrel having a shorter sight radius demands a more refined sighting system.

But if it bothers you ...

Check to make sure that your barrel is mounted perfectly centered on your receiver and not canted to the left somewhat. This may happen if the index notch in the receiver where the barrel indexing pin indexes is worn. It is an old receiver after all.

What I would do is loosen the barrel nut and see if there's any play by twisting the barrel left to right and perhaps finding a happy medium. Torque the barrel nut on making sure the barrel doesn't slip to the left again as you're torquing the nut and re-zero the rear sight when you're done.

 

[Suputin]

The barrel, on the other hand, is an ATRS 5.56 NATO 1:10.

Did I get screwed?

You bought what you thought was a POS Stag Arms AR and got a custom made, match grade stainless barrel and you figure you got screwed?

I paid $950 shipped for this rifle. What do you guys think?

IIRC that barrel sold for about $425 which is nearly half what you paid for the entire rifle. So no, you didn't get screwed, in fact you got a wicked deal.

 

[alberta tactical rifle]

We were commissioned to make a number of 10 twist barrels for a Swiss police agency.
They spec'ed the 10 twist as they are running the 63 to 69 bullet weights.
I have run 69s out of my own 9 twist barrels with excellent results.

OP for what it is worth, our custom stainless match barrels, like what you got sell for $550.00, so if you got a complete rifle for $900.00 you got a great deal assuming the rest of the rifle is not crapped out.

 

[peter2772000]

I'm sure Plink was joking with that post and probably boozing it up at the hour he posted.


Not to worry, I didn;t take it the wrong way LOL. Plink and I know each other already, I wasn't miffed when I read his post.


I wouldn't be too concerned where the rear sight aperture ended up provided you were able to zero it precisely on target. That upper was intended for a 20" barrel sight radius and your now 11.5" barrel having a shorter sight radius demands a more refined sighting system.

But if it bothers you ...

Check to make sure that your barrel is mounted perfectly centered on your receiver and not canted to the left somewhat. This may happen if the index notch in the receiver where the barrel indexing pin indexes is worn. It is an old receiver after all.

What I would do is loosen the barrel nut and see if there's any play by twisting the barrel left to right and perhaps finding a happy medium. Torque the barrel nut on making sure the barrel doesn't slip to the left again as you're torquing the nut and re-zero the rear sight when you're done.

It bothers me a bit, so I'll give it a try. Thanks for the advice.

You bought what you thought was a POS Stag Arms AR and got a custom made, match grade stainless barrel and you figure you got screwed?

IIRC that barrel sold for about $425 which is nearly half what you paid for the entire rifle. So no, you didn't get screwed, in fact you got a wicked deal.

Ok, so I've learned a few more things. Stag, caca. Alberta Tactical, yummy. Got it!

We were commissioned to make a number of 10 twist barrels for a Swiss police agency.
They spec'ed the 10 twist as they are running the 63 to 69 bullet weights.
I have run 69s out of my own 9 twist barrels with excellent results.

OP for what it is worth, our custom stainless match barrels, like what you got sell for $550.00, so if you got a complete rifle for $900.00 you got a great deal assuming the rest of the rifle is not crapped out.

Wow, I'm impressed, 'specially if that's what I have. But my barrel is not bright steel in appearance, nor is it anywhere near to a bull-barrel. If that doesn't matter, then great. Looks like I got a super deal. Thanks for the info

Guys, I don't mean to come off as either ignorant or a whiner, it's not my intent. I purchased this rifle thinking that it was a Stag Arms AR. I've owned an SP1 since the 80's, purchased used. I knew nothing about that one either until I read up on it here on CGN. Didn't even know if Stag was better or worse than any other...

Thanks for all the advice, I definitely will be putting this rifle thru the paces in the next months.

 

[alberta tactical rifle]

It bothers me a bit, so I'll give it a try. Thanks for the advice.



Ok, so I've learned a few more things. Stag, caca. Alberta Tactical, yummy. Got it!




Wow, I'm impressed, 'specially if that's what I have. But my barrel is not bright steel in appearance, nor is it anywhere near to a bull-barrel. If that doesn't matter, then great. Looks like I got a super deal. Thanks for the info

Guys, I don't mean to come off as either ignorant or a whiner, it's not my intent. I purchased this rifle thinking that it was a Stag Arms AR. I've owned an SP1 since the 80's, purchased used. I knew nothing about that one either until I read up on it here on CGN. Didn't even know if Stag was better or worse than any other...

Thanks for all the advice, I definitely will be putting this rifle thru the paces in the next months.

It may not be a bull or heavy contour as we make all sorts of different contours.
If it is mostly black in color it was Ceramic coated, but rest assured the barrel blank is a stainless matchgrade, not your typical spray and pray barrel.

 

[peter2772000]

Fantastic then. I appreciate your feedback, looks like this rifle was a better deal than I could have hoped for.