Recommendations for varmit barrel for Colt LE 6920 and BCG

[Ura-Ki]

Most forget the reasons for going to the 1/7 twist was to give back a bit of range to the short barreled M-4 and like, as well as to adequately stablise the new 77 gr ammo coming on line. My self, I like using the longer and heavier hunting ammo and needed most stabilization then the 1/9 twist gives these! I have a Rem 40X with a .223 chambered heart barrel with a 1/9 twist and it hates any thing bigger then 55 gr ammo! When I tried heavier, I would see signs of pressure increases, and the accuracy went to heck.

 

[tkdguy]

Important Question: If standard 223 is fired in 223 Wylde will the fire-formed case, then reloaded, be capable to be fired in a standard 223 chamber or 5.56 chamber? Thanks.

 

[3MTA3]

A quick review of 223 Wylde is 1:8. I'll look further. Any specific manufactures that do Wylde 1:7. I can check Brownells. Thanks.

Black Hole Weaponry/ Columbia River Arms
223 Wylde 1:8 twist. The only round that requires 1:7 to shoot well is one specific tracer round.
Melonited stainless steel
Polygonal rifling (less drag and wear than standard rifling)
Excellent reputation for accuracy
Made in St Helens, OR

I have a pair of them and no buyers remorse whatsoever.

 

[3MTA3]

Important Question: If standard 223 is fired in 223 Wylde will the fire-formed case, then reloaded, be capable to be fired in a standard 223 chamber or 5.56 chamber? Thanks.

Dimensionally the cases are the same. It a different leade length that makes the 223 Wylde different. They will reload just fine and you still use .223 dies like normal. I full size all brass I use in semi autos to ensure reliable feeding.

Don't forget a better trigger for that 6920 lower if you haven't already done so.

 

[Ura-Ki]

I do separate brass/loads specifically for my bolt action, but the ammo can work in my AR's just fine. I just seat my bullets a little further out for the bolt then the AR's.

 

[U8395279]

Coyotes. Crow.

In that case, you are getting a lot of bad advice here. .2223 Varmint ammunition is typically loaded in 40 to 55 gr bullet weights. These bullets are going to be over-stabilized in such tight twist rates.

Just take a look at any bolt action .223 varmint hunting rifle on the market, and you will see that they typically have a 1:12 twist rate.

I would not at all advise going with a twist rate tighter than 1:9, if this barrel is meant for hunting varmints.

Regarding barrel contour, I would recommend a lighter contour, to keep the rifle's weight manageable. 22 inch length would be about ideal. Definitely don't go shorter than 20 inches.

Have you looked into X-Caliber Barrels? I've been hearing lots of good things about them from AR owners.

Configure Your Custom AR-15 Barrel

.

 

[ZigZagZeke]

back up bolt. Any suggestions would be of help. What barrel length for a varmit barrel? Back up bolt carrier group recommendations. Just for back up; nothing fancy will do. Just MilSpec., and by what manufacturer? Thanks.

I would go 20", 1:7 or 1:8 twist. Fulton Armory has some nice barrels for reasonable prices. I put a stainless 24" bull barrel from Fulton Armory on my Bushmaster Varminter. I love the accuracy, but if I did it again I'd go 20".

 

[U8395279]

I would go 20", 1:7 or 1:8 twist. Fulton Armory has some nice barrels for reasonable prices. I put a stainless 24" bull barrel from Fulton Armory on my Bushmaster Varminter. I love the accuracy, but if I did it again I'd go 20".

Bull barrels are really quite heavy.

Fulton Armory barrels do indeed have an excellent reputation. Although they do not offer as many configuration options, as some other companies do.

 

[erslll]

I couldn't agree more with Lance. I have a couple of 1:8 twist barrels that shoot 55 grain VMAX pretty well. The one 1:7 barrel I have used shot the same 55 grain VMAX into shotgun sized groups. Not to say that every barrel is the same but if you did want to shoot a wider range of bullet weights, I don't understand going with the absolute fastest twist barrel you can get.

A 1:7 twist will effectively stabilize most commercially available ammo down to even below 50 grains (be careful of jacket separation below 50). And anything above it, up to 77 grains. It's kind of the "catch-all" twist rate.

Can you define "catch-all" for me?

 

[Kruel J]

Sure! 55 grain and above are the most common grain weights for .223/5.56 ammo. Yes, there are some really light loads out there, but walk through any LGS or sporting goods store and you'll see 55 grain and above for the most part. The 1:7 will stabilize them. I'm not bashing 1:8 and in fact am thinking of ordering my next upper with that twist rate. I'm just simply stating that 1:7 will more than likely stabilize a wider range of grain weights than 1:9. But hey, like you said not all barrels are created equal.

And there are several others that agree here. But Lance makes a good point that if you are shooting 40 grain varmint loads, they will probably shell their jackets and scatter like a shotgun. Cheers!

 

[Medic!]

I stick to 55gr 5.56.
My 1/7 16'' 6920 shoots it OK. M-193 goes about 2-1/2''.
But my chrome lined 1/12 18''DR-200 shoots M-193 in under an inch.

I would prefer a 1/12 colt 6920.
But 1/7 is all the rage.

 

[Medic!]

Sure! 55 grain and above are the most common grain weights for .223/5.56 ammo. Yes, there are some really light loads out there, but walk through any LGS or sporting goods store and you'll see 55 grain and above for the most part. The 1:7 will stabilize them. I'm not bashing 1:8 and in fact am thinking of ordering my next upper with that twist rate. I'm just simply stating that 1:7 will more than likely stabilize a wider range of grain weights than 1:9. But hey, like you said not all barrels are created equal.

And there are several others that agree here. But Lance makes a good point that if you are shooting 40 grain varmint loads, they will probably shell their jackets and scatter like a shotgun. Cheers!

I had a Colt sporter with a 20'' 1/7 back in 1991.
I was shooting some 55 grain ammo one day. It was probably something cheep. [I was at the time].

Every few rounds I got a grey puff about 50-80 yards down range! I had no Idea what it was at the time.

I also owned three 1986-96 mini-14's. They were known not to be too accurate.
They also had 1/7 barrels.

There 1/10 now.

Sunflower Ammo.com: Ruger Mini-14/30 Barrel Twist Rates

 

[Kruel J]

As stated, not all guns/barrels are created equal. And honestly, you can't compare a bolt action .223 to an AR platform as far as accuracy. Apples to Oranges.

@Medic! I believe Colt was the first manufacturer to produce 1:7 barrels for the M4 back in the 60's/70's to adopt to the SS109.

Here's some reading:

Early model M16 barrels had a rifling twist of 4 grooves, right hand twist, 1 turn in 14 inches (1:355.6 mm) bore - as it was the same rifling used by the .222 Remington sporting round. This was shown to make the light .223 Remington bullet yaw in flight at long ranges and it was soon replaced. Later models had an improved rifling with 6 grooves, right hand twist, 1 turn in 12 inches (1:304.8 mm) for increased accuracy and was optimized for use with the standard U.S. M193 cartridge. Current models are optimized for the heavier NATO SS109 bullet and have 6 grooves, right hand twist, 1 turn in 7 in (1:177.8 mm).[81][82][83][84] Weapons designed to accept both the M193 or SS109 rounds (like civilian market clones) usually have a 6-groove, right hand twist, 1 turn in 9 inches (1:228.6 mm) bore, although 1:8 inches and 1:7 inches twist rates are available as well.

So, the M16 uses 1:7. To stabilize 62 grain projectiles. It's known to stabilize up to 77 grains very well. And down to 55 grains with some small accuracy losses. And yes, I would say SOME barrel/projectile combos could cause jacket separation. Maybe 1:8 is really the best of both worlds. I'm sold!

 

[tkdguy]

So to replace a barrel on a Colt 6920 le for varmit with 55 grain bullets I should re-barrel with a 1:8 or 1:9 twist. Does anyone know what kind of groups I would achieve with off the shelf premium ammo or handloads with cfe and standard overall length and max allowable charges or similiar? Would the accuracy approximate that of a Rem BDL 700 223 or CZ 223??? Thanks.

Re-barrel with premium 20 inch sporter barrel and not bull barrel. thanks.

There are AR 15 barrels with 1:12 twist but that would be limited to 55 grain pills?