AR barrel length

D

dale06

Member
I have a suppressor ordered for my AR15. I plan to use it with thermal for night calling. It’s .223. What’s your recommendation for barrel length. I have a 22” barrel now. Should I cut it or leave that long. The suppressor is 6” long.
 
alf said:
I'd run it as is for now till you get more time behind it, then decide.
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This is very solid advice. As always from that guy....

You may consider a Bootleg adjustable BCG if you care about rifle tune. If not, don't worry about it.

My cat hunting rifle is a suppressed 16" er.

I hike up and down mountains for many miles with it though.

If I was on the flat lands i would want a longer barrel.
 
As you reduce velocity (muzzle) you decrease mpbr. Increase likely outcome of edge hits, heavy for caliber bullets only amplify drop past 200 yards with small cases.
 
My 223 AR is 16" sans can and works well, in fact I like it better than with my longer barreled upper.

Like others leave it as is and get a feel for how it works. Threaded barrels/upper are pretty reasonable, you could just have a second upper/barrel to experiment with.
 
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I'm in the same situation but with 24 inch barrels. I don't want to give up the velocity though. Sometimes I pass deer hunters walking out as i'm going in. Might get some interesting comments.
 
Forget about cutting the barrel, especially if its a known accurate barrel. You can buy a shorter barrel/upper for relatively cheap if needed, probably the same amount as cutting/re-crowning. Velocity loss and bullet drop will have essentially a negligible difference for hunting inside 300 yards. An 18" vs 24" 5.56/223 barrel could only have about 100fps difference.
 
joe777 said:
Forget about cutting the barrel, especially if its a known accurate barrel. You can buy a shorter barrel/upper for relatively cheap if needed, probably the same amount as cutting/re-crowning. Velocity loss and bullet drop will have essentially a negligible difference for hunting inside 300 yards. An 18" vs 24" 5.56/223 barrel could only have about 100fps difference.
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I agree with most things you said there, except the last one. Depending on the cartridge and the load, cutting off 6" of barrel could result in a mv loss of 300+fps. It can be substantial.
 
Real world numbers.....

22-204 with 80 Bergers, cut back from 24" to 18", lost 95, went from 3025 to 2930 fps, 15.8 loss per inch.

6x47 Lapua with 108 ELD's, cut back from 25" to 18", lost 180, went from 3172 to 2992 fps, 25.7 loss per inch
 
alf said:
Real world numbers.....

22-204 with 80 Bergers, cut back from 24" to 18", lost 95, went from 3025 to 2930 fps, 15.8 loss per inch.

6x47 Lapua with 108 ELD's, cut back from 25" to 18", lost 180, went from 3172 to 2992 fps, 25.7 loss per inch
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My 6arc load: 87gr v-max, 31gr leverevolution. In an 18" barrel it's 2,830fps, in a 22' barrel it's 3050fps. That 55fps per inch.
 
Hecouldgoalltheway said:
My 6arc load: 87gr v-max, 31gr leverevolution. In an 18" barrel it's 2,830fps, in a 22' barrel it's 3050fps. That 55fps per inch.
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That's not an apples to apples comparison when you consider chamber, throating, & barrel dimension differences between guns vs cutting back barrels using the same loads. It's valid for those two examples.
 
alf said:
That's not an apples to apples comparison when you consider chamber, throating, & barrel dimension differences between guns vs cutting back barrels using the same loads. It's valid for those two examples.
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Its as close as it can possibly be. Both barrels are er er shaw, same profile, twist, and identical in every way but the length. It's true of course that speed varies by barrel. I have a buddy with an 18" proof steel barrel, and he's getting about 10fps on average more than my 18". My point is that saying you'll lose 100fps in 6" isn't reliable. My 20" 6.5prc lost much more than that when I had it chopped down from 26" to 20". It was about 275fps.
 
At minimum see how it balances with the 22" barrel/suppressor. Only reason to shorten it is to improve handling/sticks/tripod use. And don't forget, to see how it carries. You won't be reducing the weight by a lot, possibly only a few oz depending on diameter so it's more about balance.
 
Hecouldgoalltheway said:
My point is that saying you'll lose 100fps in 6" isn't reliable.
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I never said nor implied that you lose 100 in 6" as gospel.

I gave exact loss per inch in 2 examples shot in the same barrel with the same ammo.

I never checked the number of rounds fired in the 22 before & after, but the 6x47 were averages of 12 rds at 25" & 15rds at 18".
 
alf said:
I never said nor implied that you lose 100 in 6" as gospel.

I gave exact loss per inch in 2 examples shot in the same barrel with the same ammo.

I never checked the number of rounds fired in the 22 before & after, but the 6x47 were averages of 12 rds at 25" & 15rds at 18".
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My reply wasn't aimed at you. You weren't the one who made that claim. I only quoted you because I was adding similar data to the conversation.
 
Hecouldgoalltheway said:
My reply wasn't aimed at you. You weren't the one who made that claim. I only quoted you because I was adding similar data to the conversation.
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10-4.....

Another thought, there's tests done in the past cutting off a barrel an inch at a time, and the loss per inch in not linear in fashion. Some cuts lost very little, while others took a big jump. Who knows why, but it happens.
 
As I age things change. I have a 20" heavy barrel predator pursuit. I quit carrying several years ago. I started carrying a 16" A4 because it is light and quick. Then got a can for it. Back to not enjoying it. I just built a 11.5" AR pistol. My hope was to end up with a SBR. I built the pistol first to be sure it would be for me before getting a tax stamp. After getting it put together I am really happy with it! After sight in the first 100 yard groups were 1/2" and just under 3/4" with a really bad mil spec trigger. I know there will be a velocity loss and I am ok with that. I will shoot thru a chronograph to satisfy my curiosity.
 
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