Home Forums Hunting & Shooting AR and Tactical Rifles Bushmaster varmit special

What his friend said is irrelevant. However, TWR you of all people, should know barrels can be very different inside even for the same caliber. Back to that in a minute.

I also thought that Colt always made 1:7 twist rifles, but I checked on the web before posting my prior comment and was surprised to see them saying 1:9 here:
http://www.colt.com/law/ar15a3.asp

The others are 1:7 as I expected them to be, but I thought the model indicated was the one with the 1:9 twist.

I'm sure the bore size will be the same for all barels: .218 with a .224 groove diameter. So what could cause one barrel to let cleaning patches go through easier than another? Anybody?

I can think of several possibilities right off the bat but in this case the Colt barrel is chrome lined, and that would be the reason.

ETA: I send before I could finish my thought. The other issue is we have no clue how many rounds have gone down the other barrels, (or even this one for that matter,) and that will also make a difference. You know how stainless steel can get in front of the chamber and that could present some resistance to the patch.

What are you, the Cheshire Cat?


Oh, I notice that I am approaching 1000 posts. I must use the remaining ones wisely.

My guess was lotsa rounds down the tube? The rifling looks a bit worn, don't have another Colt to compare it to.

Better clarify this, all groups were 3 shot, sorry guys, I'm cheap!

Keep a smile on your face and always keep em wondering...

Would you like to guess when the last 6721 run was produced?
Just because they catalog it don't mean they make em but it's all good.

weaselsRus, I used to subscribe to the 3 shot group theory due to my preference to light weight barrels (and lack of shooting ability). Now it's 5 shots at least and then that's 5 groups of 5 shots back to back. If you're gonna work on a gun and a load you should make it count and remove all doubt. Even ol Rost would be proud of me, yesterday I shot 10 shot groups to check accuracy and velocity over the chrono but I only shot 8 groups before I ran out of test ammo. I'm still the weak link in my shooting.

TWR, rost,

Tried the Fed. stuff again and it proved you right. I used a Wilson (1 1/8"), a 16" Bushmaster (1 3/4"), an Encore 28" (2"+), and a 700, about the same. 3 shot groups @ 125 yds.

Back to the original post, I have a BM 24" varmit, not stainless, the best it will do, so far is 1 1/2", using 55 gr. HPBT.