Bullet weight question 223 1:9 twist - The Firearms Forum

springerbuster · 04-02-2011, 12:39 AM

I have a Bushmaster carbon 15 with a 14 1/2" barrel that has a 1:9 twist rate. I am not happy with the accuracy I am getting from 55gr bullets. So far this is the only bullet weight that I have shot through it, some reloads and some factory ammo. I am just wondering if I would have better luck with a heavier bullet. Sorry this may be a question that belongs on another thread. Any help would be appreciated.

steve4102 · 04-02-2011, 01:29 AM

Lets talk reloads (handloads). What 55gr bullet/bullets have you tried? The better the bullet the better the accuracy. Cheap bullets are cheap for a reason and they usually do not produce the best accuracy.

Speaking of accuracy, what exactly do you mean by "unhappy" as it relates to group size and target distance?

IMO the bullet is the number one accuracy component in a handload. That said, powder plays a huge roll as well, what are some of the powders and charge weights you have tried so far?

I have a 1-9 twist Colt that shoots 50-69gr bullets well, 69 being the heaviest(longest).

muddober · 04-02-2011, 01:52 AM

With that fast a twist you would in my opinion be better off shooting 60 grain plus weight bullets.

Ron

retired grunt · 04-02-2011, 05:51 AM

My bushmaster delivers better accuracy with heavier bullets, try some 69 grain rounds.

jack404 · 04-02-2011, 06:39 AM

heavier is better down under too

springerbuster · 04-02-2011, 10:04 AM

Thanks for your replies. The recipe I have been using is 24gr of AA2230c with a Hornady 55gr fmjbt or 55gr Vmax bullet. I should add that I have an Eotech red dot sight on my gun as well. I have a range at my house that is 80 yds and I have been getting about 3" groups at that distance. So another question. Could my problem be the red dot scope?

jack404 · 04-02-2011, 10:07 AM

red dot is not a accurate grouping sight by any means , i have them myself , i like em, but i wont try to qualify for a competition with one unless its a fast shoot ( close in , mobile targets )

American Leader · 04-02-2011, 01:09 PM

I thought the 1:9 twist was stardard on .223? Also, regarding 55 grain bullets, you boy's seen my grouping when I loaded my new Rem 700 VTR with Rem. 55 gr. HP & 27.5C varget, about 3/4" group to start. There was a big difference between 25.5, 26.5, and the 27.5C loads. However, the VTR has a 22" barrel length. Springerbuster may have to find his guns sweet spot?

bmg50doorgunner · 04-02-2011, 01:22 PM

1:9 twist is considered a fast barrel for a .223. Fast barrels work well with heavier bullets, while slow barrels (1:12 twist) work well with lighter ones (50-55gr).

The USMC Colt M-16A2 and A4 had 20" (1:12) barrels ideally suited for 55gr FMJ.

Your (1:9) 14.5" barrel is ideally suited to heavier bullets. I agree with "Retired Grunt", try some 69gr.

I load Hornady 68gr FMJ and Sierra Match King 69gr FMJ for my (1:9) 16" Colt M4 and achieve 1/2" MOA. BTW, your Bushmaster Carbon 15 is one of my personal favorites... a great rifle!

Claude Clay · 04-02-2011, 01:36 PM

go to 62gr. 69 is for 1/7. 55 for 1/10 and up.
how many rounds through it so far? i don't buy into bbl break ins (for your getup) but seasoning a bbl is understandable. couple hundred rounds of copper bullets, cleaning after each 50 and no mag dumps. pace yourself by scoping each round.
eotec is darn nice as has been noted, but for accuracy glass is necessary.

RustyFN · 04-02-2011, 02:38 PM

Quote:

1:9 twist is considered a fast barrel for a .223.

A 1:9 is pretty standard for all of the AR's I have seen. A fast twist AR will be 1:7 twist. A 1:9 twist won't stablaize a bullet over 69 grains very well. I load the same Hornady 55 grain FMJ-BT for my Rock River 16" with 1:9 twist and get very good accuracy. I had four exploding target set at 100 yards. The spot you have to hit to set them off is the size of a quarter. It took me four shots to explode the four targets. That was with my front elbow resting on a table. I'll take that kind of accuracy any time.

springerbuster · 04-02-2011, 08:38 PM

Thanks for all your help. I was already debating trying a different type of scope. Now I think I will, along with a heavier bullet.

guntech59 · 04-10-2011, 01:32 PM

Quote:

Originally Posted by bmg50doorgunner

1:9 twist is considered a fast barrel for a .223. Fast barrels work well with heavier bullets, while slow barrels (1:12 twist) work well with lighter ones (50-55gr).

The USMC Colt M-16A2 and A4 had 20" (1:12) barrels ideally suited for 55gr FMJ.

Your (1:9) 14.5" barrel is ideally suited to heavier bullets. I agree with "Retired Grunt", try some 69gr.

I load Hornady 68gr FMJ and Sierra Match King 69gr FMJ for my (1:9) 16" Colt M4 and achieve 1/2" MOA. BTW, your Bushmaster Carbon 15 is one of my personal favorites... a great rifle!

Ahhhhh, no! M16A2 and newer variants all had 1/7" twists.

Boris · 04-10-2011, 08:14 PM

Quote:

Originally Posted by RustyFN

A 1:9 is pretty standard for all of the AR's I have seen. A fast twist AR will be 1:7 twist. A 1:9 twist won't stablaize a bullet over 69 grains very well. I load the same Hornady 55 grain FMJ-BT for my Rock River 16" with 1:9 twist and get very good accuracy. I had four exploding target set at 100 yards. The spot you have to hit to set them off is the size of a quarter. It took me four shots to explode the four targets. That was with my front elbow resting on a table. I'll take that kind of accuracy any time.

Its not the weight that counts, its the length. The 62 grain projectile in M855 ball is as long as a 71 grain all lead core projectile. The less dense steel portion of the M855 projectile makes it longer for its weight.

I have seen more than plenty of 1:9 twist barrels turn out spectacular groups with 75 grain projectiles.

gun-nut · 04-10-2011, 09:25 PM

I have the howa 1500 and the speer 55gr sp works well. I use 22.5 gr. of IMR 4198 and put them hole for hole on a calm day low humidity. On high humid days with wind i still clover leaf. Thats at 200 yards. If my mind serves me right i have a 1:10 twist and a 22" bbl.

04-02-2011, 12:39 AM	#1
springerbuster V.I.P. Member Join Date: Sep 2009 Location: Southwest Washington Posts: 154	Bullet weight question 223 1:9 twist I have a Bushmaster carbon 15 with a 14 1/2" barrel that has a 1:9 twist rate. I am not happy with the accuracy I am getting from 55gr bullets. So far this is the only bullet weight that I have shot through it, some reloads and some factory ammo. I am just wondering if I would have better luck with a heavier bullet. Sorry this may be a question that belongs on another thread. Any help would be appreciated. -->

04-02-2011, 01:29 AM	#2
steve4102 Former Guest Join Date: Jan 2006 Location: Minnesota Contributor Posts: 2,760	Re: Bullet weight question 223 1:9 twist Lets talk reloads (handloads). What 55gr bullet/bullets have you tried? The better the bullet the better the accuracy. Cheap bullets are cheap for a reason and they usually do not produce the best accuracy. Speaking of accuracy, what exactly do you mean by "unhappy" as it relates to group size and target distance? IMO the bullet is the number one accuracy component in a handload. That said, powder plays a huge roll as well, what are some of the powders and charge weights you have tried so far? I have a 1-9 twist Colt that shoots 50-69gr bullets well, 69 being the heaviest(longest).

04-02-2011, 01:52 AM	#3
muddober Advanced Senior Member Join Date: Sep 2008 Posts: 1,436	Re: Bullet weight question 223 1:9 twist With that fast a twist you would in my opinion be better off shooting 60 grain plus weight bullets. Ron

04-02-2011, 05:51 AM	#4
retired grunt V.I.P. Member Join Date: Mar 2009 Location: Northern NY Posts: 416	Re: Bullet weight question 223 1:9 twist My bushmaster delivers better accuracy with heavier bullets, try some 69 grain rounds.

04-02-2011, 06:39 AM	#5
jack404 Former Guest Join Date: Jan 2010 Location: Australia Contributor Posts: 17,622	Re: Bullet weight question 223 1:9 twist heavier is better down under too

04-02-2011, 10:04 AM	#6
springerbuster V.I.P. Member Join Date: Sep 2009 Location: Southwest Washington Posts: 154	Re: Bullet weight question 223 1:9 twist Thanks for your replies. The recipe I have been using is 24gr of AA2230c with a Hornady 55gr fmjbt or 55gr Vmax bullet. I should add that I have an Eotech red dot sight on my gun as well. I have a range at my house that is 80 yds and I have been getting about 3" groups at that distance. So another question. Could my problem be the red dot scope?

04-02-2011, 10:07 AM	#7
jack404 Former Guest Join Date: Jan 2010 Location: Australia Contributor Posts: 17,622	Re: Bullet weight question 223 1:9 twist red dot is not a accurate grouping sight by any means , i have them myself , i like em, but i wont try to qualify for a competition with one unless its a fast shoot ( close in , mobile targets )

04-02-2011, 01:09 PM	#8
American Leader Advanced Senior Member Join Date: Mar 2011 Location: Iowa Contributor Posts: 1,630	Re: Bullet weight question 223 1:9 twist I thought the 1:9 twist was stardard on .223? Also, regarding 55 grain bullets, you boy's seen my grouping when I loaded my new Rem 700 VTR with Rem. 55 gr. HP & 27.5C varget, about 3/4" group to start. There was a big difference between 25.5, 26.5, and the 27.5C loads. However, the VTR has a 22" barrel length. Springerbuster may have to find his guns sweet spot?

04-02-2011, 01:22 PM	#9
bmg50doorgunner Member Join Date: Jan 2010 Posts: 8	Re: Bullet weight question 223 1:9 twist 1:9 twist is considered a fast barrel for a .223. Fast barrels work well with heavier bullets, while slow barrels (1:12 twist) work well with lighter ones (50-55gr). The USMC Colt M-16A2 and A4 had 20" (1:12) barrels ideally suited for 55gr FMJ. Your (1:9) 14.5" barrel is ideally suited to heavier bullets. I agree with "Retired Grunt", try some 69gr. I load Hornady 68gr FMJ and Sierra Match King 69gr FMJ for my (1:9) 16" Colt M4 and achieve 1/2" MOA. BTW, your Bushmaster Carbon 15 is one of my personal favorites... a great rifle!

04-02-2011, 01:36 PM	#10
Claude Clay V.I.P. Member Join Date: May 2009 Location: Central CT Posts: 451	Re: Bullet weight question 223 1:9 twist go to 62gr. 69 is for 1/7. 55 for 1/10 and up. how many rounds through it so far? i don't buy into bbl break ins (for your getup) but seasoning a bbl is understandable. couple hundred rounds of copper bullets, cleaning after each 50 and no mag dumps. pace yourself by scoping each round. eotec is darn nice as has been noted, but for accuracy glass is necessary. __________________ teachers may learn you the rules; experience will teach you the exceptions. NRA Instructor Last edited by Claude Clay; 04-02-2011 at 01:42 PM..

04-02-2011, 08:38 PM	#12
springerbuster V.I.P. Member Join Date: Sep 2009 Location: Southwest Washington Posts: 154	Re: Bullet weight question 223 1:9 twist Thanks for all your help. I was already debating trying a different type of scope. Now I think I will, along with a heavier bullet.

04-10-2011, 09:25 PM	#15
gun-nut Senior Member Join Date: Jan 2011 Location: ohio Contributor Posts: 931	Re: Bullet weight question 223 1:9 twist I have the howa 1500 and the speer 55gr sp works well. I use 22.5 gr. of IMR 4198 and put them hole for hole on a calm day low humidity. On high humid days with wind i still clover leaf. Thats at 200 yards. If my mind serves me right i have a 1:10 twist and a 22" bbl. __________________ Don't retreat just reload.