Rebarrel to Sabre M4 or BCM Middy?

[Amicus]

Looking for opinions here. Due to Massachusett[e]s’ repressive laws, the old federal “AW” ban is still alive and well here. I have several Colt preban lowers that really deserve an upgrade from old A2-style rifle configurations. I also have a RRA upper that has been nothing but a PIA due to the heavy mid-length barrel I have on there (now with a pinned muzzle break due to a YHM screw up). There is nothing wrong with the upper, except it always seems to have the wrong barrel.

Choices (costs do not include shipping):

BCM mid-length upper (1 in 7”, cost $425), or,

Rebarrel the RRA upper to take a Sabre M4 flat top barrel with flip-up front sight (chrome lined, 1 in 9”, new gas tube, cost $318).

I have all the proper tools to do the rebarrel job (receiver block, armorer and other tools, and I have to buy a torque wrench anyway), but I have never rebarrelled a rifle before.

One additional fact: here in Mass it is very difficult to find ammunition; many dealers will not ship here and getting longer/heavier bullet types is a problem. 1 in 7” twists are fine, but most of what is available here is 55 grain M193, which would behave better after 120+ yards in a 1 in 9” barrel. I plan to shoot out to 200 yards. I already have several 1 in 7" rifles.

Any thoughts? :confused:

[Boss Hogg]

when you say "pre ban", is it a Colt made before 10/94?

If so, I'm guessing it has a .315" front takedown pin. If that's the case, you'd want to get conversion pins to be able to use it with a current .250" upper. I can't remember where I got my Colt OEM conversion pin- it's been years. Otherwise, you'd need a Daniel Defense "Big Hole Upper" with the appropriate feed ramps.

1/7 twist is fine for accuracy with 55/62 grain ammo.

[Amicus]

I have both small hole and big hole lowers. Yes, they are real assembled prebans (prior to 9/13/94). I am familiar with the conversion pins.

[USMC03]

If the Sabre barrel is a 16", the mid-length has the advantage for several reasons.

These articles may provide some food for thought:


http://www.03designgroup.com/photo/carbine-vs-midlength/icon-carbine-vs-midlength.jpg
03designgroup | Carbine vs. Mid-Length Gas System on a 16" Barrel http://demigodllc.com/icon/extwh3.png (http://www.03designgroup.com/technotes/carbine-vs-mid-length-gas-system)


http://www.03designgroup.com/photo/midlengths-for-leo/icon-midlengths-for-leo.jpg
03designgroup | Advantages of Mid-Length Carbines for Law Enforcement Officers http://demigodllc.com/icon/extwh3.png (http://www.03designgroup.com/technotes/midlengths-for-leo)



I shoot 55 grain XM193, Winchester Q3131A, Federal American Eagle, Black Hills, (etc) with 1/7", 1/8", and 1/9" twist barrels (Colt, LMT, BCM) out to 425 yards on smaller than average targets with no issues as long as I do my part (local run and gun rifle match). Pics of the targets and pic of me shooting a Colt LE6920 (1/7" twist with 55 grain ammo) can be seen here:

http://www.03designgroup.com/photo/which-carbine-is-more-accurate/icon-which-carbine-is-more-accurate.jpg
03designgroup | Which Carbine Is More Accurate http://demigodllc.com/icon/extwh3.png (http://www.03designgroup.com/technotes/which-carbine-is-more-accurate)



Hope this helps

[Amicus]

Boss,

I didn't mean to be curt, but I have been through this before.

I own rifles with 1/7, 1/8, and 1/9 twists, and, although it may be my own fault, I have found that the 55 gr. projectiles start to fall off in accuracy after about 120 yards or so when fired out of a 1/7. It may be a combination of barrel profile, the particular rifle, who knows?

Still and all, the odds that I will be shooting anything over 69 gr. from a 16" bbl are very slim. From everything I think that I know (:D) the 1 in 9" will serve well in that capacity.

[5pins]

I like the 1/7 better then the 1/9 but, I think you should get the Saber. This way you can put those tools to work. You will have fun doing it and the satisfaction of shooting something you built.

[cobb]

If you are happy with the RRA accuracy you could send it to ADCO or somewhere else to get reprofiled. Although both choices have better steel if that is also what you are after. Also good luck on Brown's election.

[MarshallDodge]

I have seen accuracy issues using 55 grain bullets with 1:7 twist barrels as well.

My needs include the ability to shoot a 50 grain VMax so I recently picked up the 16" 1:8 twist Sabre Defense barrel at the bottom of this page (http://www.pkfirearms.com/content/1/20/65/85) for this reason.

[Amicus]

If you are happy with the RRA accuracy you could send it to ADCO or somewhere else to get reprofiled. Although both choices have better steel if that is also what you are after. Also good luck on Brown's election.

Thanks for the good word for Brown. I met him when he ran for state senator and liked him. Although not in my district, I supported him because he was running against the obnoxiously anti-gun Angus McQuillken. It's a long and tiresome and very Massachusetts story.

That bbl is quite accurate, easily 1 MOA, but I have no use for it. With no chrome in the tube or the chamber and a now a pinned brake, it is now my third best target upper and unpleasant to shoot. Great, just what I needed. I am trying to decide now what I should do with this confabulation of useless (for me) parts.

It would probably make for sense for me just to toss the whole shebang on to the shelf and go with a new upper. But, what am I to do with all those tools I have barely used?

[Amicus]

I have seen accuracy issues using 55 grain bullets with 1:7 twist barrels as well.

My needs include the ability to shoot a 50 grain VMax so I recently picked up the 16" 1:8 twist Sabre Defense barrel at the bottom of this page (http://www.pkfirearms.com/content/1/20/65/85) for this reason.

Interesting idea, but I was looking at something a bit lighter. I am now toying with this (Sabre SPR: 1/8", 16", mid-length, fluted):

http://www.impactguns.com/store/50085.html

Is this the same barrel with a bit more hardware?

[MarshallDodge]

Interesting idea, but I was looking at something a bit lighter. I am now toying with this (Sabre SPR: 1/8", 16", mid-length, fluted):

http://www.impactguns.com/store/50085.html

Is this the same barrel with a bit more hardware?

Yes, it is the same one but with more hardware.

The one on Impact Guns site is the one I purchased when they were having a sale at their store in Ogden, UT. I didn't realize that they had them posted online so I posted the one from PK's site.

[Amicus]

Marshall:

I blew it on the specs. I believe you purchased a 16" bbl, which is a lot more acceptable to me (though I still don't know what I will do).

I read a review on Midway (re the 18" version) that the 410 SS bbl required modifications to "mil-spec" handguards and to the gas tube. True?

[NOTE: Are there really mil-spec mid-length handguards?]

In the meantime, I will vote for Mr. Brown. This rebarrel job will be my little reward for his victory, and, my newest stimulus package. Although I take the mid-length caveats seriously, I wouldn't mind having this new bbl in a carbine version; I have plans for mid-lengths in the Spring.

[ccoker]

Interesting idea, but I was looking at something a bit lighter. I am now toying with this (Sabre SPR: 1/8", 16", mid-length, fluted):

http://www.impactguns.com/store/50085.html

Is this the same barrel with a bit more hardware?



that's the barrel I have, 16" fluted stainless, 1 in 8, midlength, 5.56 chambering
it loves Tap 75g, that's 1/2" groups
also likes 64g Golddot
never had a single issue with it and has fed everything I have thrown at it
and I have done training with it with high round count

[MarshallDodge]

Marshall:

I blew it on the specs. I believe you purchased a 16" bbl, which is a lot more acceptable to me (though I still don't know what I will do).

I read a review on Midway (re the 18" version) that the 410 SS bbl required modifications to "mil-spec" handguards and to the gas tube. True?

[NOTE: Are there really mil-spec mid-length handguards?]

In the meantime, I will vote for Mr. Brown. This rebarrel job will be my little reward for his victory, and, my newest stimulus package. Although I take the mid-length caveats seriously, I wouldn't mind having this new bbl in a carbine version; I have plans for mid-lengths in the Spring.
Yes, I purchased the 16" barrel.

I am putting a free floating VTAC on mine so I don't know about the handguards but I see no reason why they would not work.

[MarshallDodge]

that's the barrel I have, 16" fluted stainless, 1 in 8, midlength, 5.56 chambering
it loves Tap 75g, that's 1/2" groups
also likes 64g Golddot
never had a single issue with it and has fed everything I have thrown at it
and I have done training with it with high round count

Thanks for the review. I wanted something that would cover the gamut from shooting varmints to home defense. It sounds like this will be the ticket.