AR-15 Barrel Length Change

[pccraig]

Service rifle competition.

For the past few years I've been shooting SR competition with a standard Colt HBar A2 with a 20" 1:7 barrel and iron sights.

My go to load included a Nosler CC 77g bullet.

I've recently completed a new build. A 16" M4 style rifle with a mid-length gas system and a 1:9 twist with the Hi-lux 1-4.5 optic.

Now I'm wondering with the shorter barrel and "lighter" twist, should I downsize the projectile.

Any insights would be appreciated.

 

[GSS]

Service rifle competition.

For the past few years I've been shooting SR competition with a standard Colt HBar A2 with a 20" 1:7 barrel and iron sights.

My go to load included a Nosler CC 77g bullet.

I've recently completed a new build. A 16" M4 style rifle with a mid-length gas system and a 1:9 twist with the Hi-lux 1-4.5 optic.

Now I'm wondering with the shorter barrel and "lighter" twist, should I downsize the projectile.

Any insights would be appreciated.

If you are or plan on shooting Service Rifle out to 600 yards you should go back to a 20" 1x7 or 1-8 twist barrel so you can shoot 75 and 77gr bullets in the 200 and 300 yard stages and the 80 grain projectiles at 600.

If you only shoot 100 - 200 yard reduced course service rifle matches you would be ok with a 16" 1x9 twist with 69 grain projectiles.

The Hi-lux is a decent scope for either
George

Edited to add:
For full distance / 600 yard service rifle competition;
The White Oak / Wilson button rifled 1x7 Service rifle barrels are considered by many, many service rifle shooters to be one of the best values for a service rifle barrel if you shoot 3000 rounds or less per season. (Normally $220 on Sale in Jan for $198)
https://www.whiteoakarmament.com/custom-post-ban-service-rifle-barrel.html

If you shoot closer to 5000 rounds or more per season you should go cut rifled;
Kreiger or Bartlein ( Both Normally $470, on Sale thru Jan for $423 )
https://www.whiteoakarmament.com/white-oak-precision-service-rifle-barrels.html

https://www.whiteoakarmament.com/white-oak-precision-service-rifle-barrels-1798.html
All are great barrels !

Frank White / Compass Lake Engineering is another great source for quality uppers and barrles
https://compasslake.com/

 

[Andy Legg]

My son shoots a 16" Wilson 1/8 twist Bull Barrel at 600 Yards in Mid-Range Prone Tactical(AR). Our handloads are running about 2575 fps @ 60F(Just above sea level). His shows to be slightly over stabilized with a Miller Stability Index of around 1.7 to 1.8.

If you already have the 16" I'd consider giving either the 75 Grain Hornady's or the 77 SMK's a shot. You might be pleasantly surprised. Miller Stability Shows to be around 1.35-1.4 depending on the temperature/velocity. Note: I think for Full Stability some/most folks would prefer to see index closer to 1.5 than 1.3.

I'd give it a shot if it were mine.....Andy

 

[Dusty Stevens]

I can fully recommend compass lake.

 

[Rsadams]

With the 1/9 the 77gr might be trouble , the only way to tell is test... If not then you go to the 69gr.... I think you may be going backwards....

 

[GSS]

Service rifle competition.

For the past few years I've been shooting SR competition with a standard Colt HBar A2 with a 20" 1:7 barrel and iron sights.

My go to load included a Nosler CC 77g bullet.

I've recently completed a new build. A 16" M4 style rifle with a mid-length gas system and a 1:9 twist with the Hi-lux 1-4.5 optic.

Now I'm wondering with the shorter barrel and "lighter" twist, should I downsize the projectile.

Any insights would be appreciated.

I typed out a detailed response to you above in an effort to help you and answer your questions.

Can you respond regarding;
What distances are the Service Rifle Matches you compete in shot from?

Reduced course from 100, 200, 300 or 500 yards?
Or
Full Distance out to 600 yards

George

 

[SPQR70AD]

With the 1/9 the 77gr might be trouble , the only way to tell is test... If not then you go to the 69gr.... I think you may be going backwards....

they have 77 gr bullets that are shorter (less BC) then the 75-80 in order to function in an AR mag and will stabilize in a 1x9

 

[SPQR70AD]

If you are or plan on shooting Service Rifle out to 600 yards you should go back to a 20" 1x7 or 1-8 twist barrel so you can shoot 75 and 77gr bullets in the 200 and 300 yard stages and the 80 grain projectiles at 600.

If you only shoot 100 - 200 yard reduced course service rifle matches you would be ok with a 16" 1x9 twist with 69 grain projectiles.

The Hi-lux is a decent scope for either
George

Edited to add:
For full distance / 600 yard service rifle competition;
The White Oak / Wilson button rifled 1x7 Service rifle barrels are considered by many, many service rifle shooters to be one of the best values for a service rifle barrel if you shoot 3000 rounds or less per season. (Normally $220 on Sale in Jan for $198)
https://www.whiteoakarmament.com/custom-post-ban-service-rifle-barrel.html

If you shoot closer to 5000 rounds or more per season you should go cut rifled;
Kreiger or Bartlein ( Both Normally $470, on Sale thru Jan for $423 )
https://www.whiteoakarmament.com/white-oak-precision-service-rifle-barrels.html
80 gr bullets in an AR will have to be single loaded at 600 yds. not a problem if set up right
https://www.whiteoakarmament.com/white-oak-precision-service-rifle-barrels-1798.html
All are great barrels !

Frank White / Compass Lake Engineering is another great source for quality uppers and barrles
https://compasslake.com/

 

[GSS]

they have 77 gr bullets that are shorter (less BC) then the 75-80 in order to function in an AR mag and will stabilize in a 1x9

Please provide a link as I have never seen or heard of these.
Also please let us know if you personally have had them work in a 1x9 twist beyond 100 yards.

I am referring to the topic of this thread. 16" or 20" service rifles.
Longer barrels on bolt guns or gas guns with longer than 20" barrels is a whole different story

70 grain VLD's may stabilize in "SOME" 1x9 20" barrels
My 1st Service rifle was a 20" 1x9 twist that I used with 69's for 200 yard reduced matches when I was starting out over 15 years ago. They shot great.

Once I wanted to graduate to shooting full distance I tried 70, vld's, 75 gr Hornady's and 77 grain Sierra's.
None of them would stabilize at 200 yards in that barrel.

Barrels are the least expensive component in Service Rifle Competition.

Honest / Simple Question
Your time, components and traveling to matches is where most of the money is spent.
Why spend all that travelling with an inferior barrel / bullet combo when it costs about the same to go with a 20" 1x7 or 1x8 twist barrel ?

If one is absolutely set on using a 1x9 twist there are only a few bullet options I know of that "MAY WORK" in a 20" 1x9.

Possibly a 16" 1x9 also but less likely.

https://www.midsouthshooterssupply....in-match-target-(vld)-very-low-drag-100-count

https://www.midsouthshooterssupply....4-diameter-70-grain-gmx-hollow-point-50-count

https://www.midsouthshooterssupply....ter-70-grain-boat-tail-hp-rdf-match-100-count

Most of this discussion is moot to help the original poster (pccraig) until he/she responds what distance they will be competing at.

 

[SPQR70AD]

GSS: I had a savage HB 1x9 and a lot of 75 gr A-Max for another rifle with 1x8 which shot great. I tried the 75 A max in the 1x9 savage and they sprayed would not stabilize. so in the Hornady manual they said that their 75 gr BTHP would work in an AR mag. so I figured it had to be shorter and might work in the 1x9 savage. I guessed right for once and they produced one ragged hole groups. being shorter they lose some BC to the longer 75 grain bullets. .395 to .467. hornady now has 73 gr ELD match sporting .398 BC and still has the 75 gr BTHP. so if I was you I would get a box of each they are cheap for such good bullets and you will have a 90% chance one or both will give you the results you want. like to hear how you make out

 

[GSS]

GSS: I had a savage HB 1x9 and a lot of 75 gr A-Max for another rifle with 1x8 which shot great. I tried the 75 A max in the 1x9 savage and they sprayed would not stabilize. so in the Hornady manual they said that their 75 gr BTHP would work in an AR mag. so I figured it had to be shorter and might work in the 1x9 savage. I guessed right for once and they produced one ragged hole groups. being shorter they lose some BC to the longer 75 grain bullets. .395 to .467. hornady now has 73 gr ELD match sporting .398 BC and still has the 75 gr BTHP. so if I was you I would get a box of each they are cheap for such good bullets and you will have a 90% chance one or both will give you the results you want. like to hear how you make out

After getting rid of that 1st 1x9 twist service rifle barrel I have only shot 1x7 twist 20" service rifle barrels of the 3 brands I linked to in my 1st response in this thread ( plus a Satern and a Pac Nor ) and haven't looked back.

I only shoot full distance (600 yards ) service rifle matches so I'd never consider putting another 1x9 twist on any of my service rifle uppers.

Everything I have typed out here to try to help pccraig;
I am referring to the topic of this thread. 16" or 20" service rifles.
Longer barrels on bolt guns or gas guns with longer than 20" barrels is a whole different story and a whole separate conversation. Apples to Oranges so to speak

 

[SPQR70AD]

After getting rid of that 1st 1x9 twist service rifle barrel I have only shot 1x7 twist 20" service rifle barrels of the 3 brands I linked to in my 1st response in this thread ( plus a Satern and a Pac Nor ) and haven't looked back.

I only shoot full distance (600 yards ) service rifle matches so I'd never consider putting another 1x9 twist on any of my service rifle uppers.

Everything I have typed out here to try to help pccraig;
I am referring to the topic of this thread. 16" or 20" service rifles.
Longer barrels on bolt guns or gas guns with longer than 20" barrels is a whole different story and a whole separate conversation. Apples to Oranges so to speak

going by what you posted I still thought you had the 1x9 barrel cause you asked me for a link and if I had shot the shorter 75 gr bullet

 

[GSS]

going by what you posted I still thought you had the 1x9 barrel cause you asked me for a link and if I had shot the shorter 75 gr bullet

have 77 gr bullets that are shorter (less BC) then the 75-80 in order to function in an AR mag and will stabilize in a 1x9

That was to help the original poster if he/she is dead set on using a 1x9 twist service rifle barrel.
Also info for me to help others that I come across in the future in the same boat as pccraig.

I run a service rifle clinic at my club each April and we get up to 48 attendees.
some of them have 1x9's until they can afford a better service rifle barrel.

If you could provide the links to the 77 gr bullets you mentioned that are shorter and will work in a 20" ( or shorter ) 1x9 twist barrel I am still interested in the info.

Huge Thanks, George
https://nfga.org/leveridge-range/

 

[SPQR70AD]

do not know how to do a link lol. I don't even have a smart phone. the bullet is the Hornady 75 gr BTHP. they have a 75 and 73 gr both ELD match bullets. I would say the 73gr would be OK but I did not test it. stay with the 75 gr BTHP. very easy to order on the internet or buy in a well stocked store. if you have the last 2 Hornady reloading manuals that bullet is in both of them and in the older manual it says the 75 gr BTHP was made to function in an AR mag

 

[Dusty Stevens]

do not know how to do a link lol. I don't even have a smart phone. the bullet is the Hornady 75 gr BTHP. they have a 75 and 73 gr both ELD match bullets. I would say the 73gr would be OK but I did not test it. stay with the 75 gr BTHP. very easy to order on the internet or buy in a well stocked store. if you have the last 2 Hornady reloading manuals that bullet is in both of them and in the older manual it says the 75 gr BTHP was made to function in an AR mag

I shoot probably 2000 of these in a slow year mag fed in a cle chamber. Its like they were made for mag feeding in an ar if you have a good chamber without a 2’ freebore

 

[GSS]

Service rifle competition.

For the past few years I've been shooting SR competition with a standard Colt HBar A2 with a 20" 1:7 barrel and iron sights.

My go to load included a Nosler CC 77g bullet.

I've recently completed a new build. A 16" M4 style rifle with a mid-length gas system and a 1:9 twist with the Hi-lux 1-4.5 optic.

Now I'm wondering with the shorter barrel and "lighter" twist, should I downsize the projectile.

Any insights would be appreciated.

pccraig,
Looks like you're not interested in any of the feedback that was posted here for you.

Was any of it helpful to you ?
George

Edited to Add:
Maybe this wasn't even intended as a serious question and was just a joke post

 

[Zero333]

Hornady 75 gr BTHP shoot awesome in my 20" R700 with 9" twist.
77 SMK shoot almost as good too.

 

[SPQR70AD]

pccraig,
Looks like you're not interested in any of the feedback that was posted here for you.

Was any of it helpful to you ?
George

looks like a drive by