1:7 Twist 16" AR Barrel... Bullet Weight?

[Saluki91]

I loaded the last of my Hornady 62gr FMJBT (C) (catalog #22760b) today, and want to replenish my stash. They will be shot through a PSA 1:7 16" Stainless Freedom Barrel. It is a fun rig for plinking, but 100 yard groups are... not tight. 2" is a very good (and rare) group.

I'm torn between buying the same bullets (they are available, and priced right), or looking for something that might bring more accuracy/consistency to the party. My questions:

Assuming I do my part (at the loading bench and behind the trigger), can a different bullet get me close to MOA at 100 yards with that barrel, or am I already getting the most it has to offer?

If there is more accuracy to be had, is the 1:7 inherently happier with 62gr and heavier bullets, or can I get away with something lighter (ie. 55gr BTHP)?

Thanks for any insight you can offer!

 

[mavracer]

1 in 7 should shoot pretty much any weight 55 and up it'll maybe favor heavier but you'd probably see more gain going from FMJ to JHP than just going heavier.

 

[Blue68f100]

Try the RMR 69gr HPBT bullet. It should shoot nice with your twist rate.

 

[Bfh_auto]

The bullet is more important than the weight as long as it stabilizes.
In general a flat base bullet will out shoot a boat tail at close range.
But I get good results from most bthp.
If price is a factor. Try a 55 soft point instead of fmj bullets.

I haven't used rmr bullets. So I can't vouch for them. But there are guys on here that can.
My gold standard is the 77smk or 77CC. If your 1-7 doesn't like either. It's problem is most likely mechanical or shooter.

 

[Saluki91]

The bullet is more important than the weight as long as it stabilizes.
In general a flat base bullet will out shoot a boat tail at close range.
But I get good results from most bthp.
If price is a factor. Try a 55 soft point instead of fmj bullets.

I haven't used rmr bullets. So I can't vouch for them. But there are guys on here that can.
My gold standard is the 77smk or 77CC. If your 1-7 doesn't like either. It's problem is most likely mechanical or shooter.

Thanks! I fully recognize that the weakest link in this system is me! ; - )

 

[Bfh_auto]

Thanks! I fully recognize that the weakest link in this system is me! ; - )

I wouldn't guarantee that. My AR runs 3/4 to 1" for 5 shots with SMKs. But it runs about a 3" pattern using fmjs.

 

[jmr40]

Most FMJ bullets aren't meant for best accuracy regardless of weight. If you're willing to accept 2" groups as good enough (and it is for most uses), then keep using what you've been using. If you want better accuracy you're going to have to buy better bullets.

I don't handload for 223, but have done well with bullets as light as 50 gr from a 7 twist. That is probably right at the limits for weight, and not all bullets that light might work.

 

[Charlie98]

There are a number of factors for AR accuracy... besides the bullet. As was mentioned, most FMJ bullets are not really intended for accuracy, you will need to step up to a better bullet, although I’ll admit, Hornady FMJ’s are prolly the best of the bunch. Try an open tip bullet, like Hornady’s 62grn BTHP.

the other big factor is the AR barrel itself, and if it’s trued up to the receiver. I had a DPMS Oracle with an M4 profile barrel, it would deflect 5” low and left at 100yds when I was slung up. I never knew if it was the barrel, or if it was not trued to the upper... or both.

 

[webrx]

I have had good luck with 69s have not shot 75 or 77 yet in my 1/7

 

[stillquietvoice]

I've used 50, 55, and 68 hornandy bullets in my psa 16" 1:7 twist AR, I get about 1.5" with them some are closer to 1.250 at 100. Irons ate harder and only get about 2" I will be trying trying out some 60 hornandy flat base and 65 gr gamekings soon.

 

[JeeperCreeper]

I have a 1:7 PSA stainless 16" as well. Honestly, accuracy sucks. Like 4 MOA. It prefers heavier, but it still doesn't matter.

It's a fine package, but precision it is not.

I'd swap the barrel. And I would probably swap it on mine of I didn't have better options, maybe one day.

 

[GooseGestapo]

I have a Wilson match 1/8” twist 20” HB in a RRA National Match AR. It shoots 80gr Sierra MK to 1/2moa at 600yds.
I have a FN (PSA) barreled A3 upper 1/7” (20” A2 w/flat top receiver). It shoots 55gr Hornady BtSpt to 7/8” at 100yds. Likewise the 75gr Hornady BTHPT Match bullet.
It shoots nearly as good as the full blown match gun.
I’d shoot any bullet under 90gr in it with confidence.

 

[Hugger-4641]

Most Ar mags won't allow anything more than a 77gr.
The most accurate bullet I've found so far is Hornady's 75gr BTHP. I'm getting a 1 1/2" group at 300yds with these in my 1/7 custom 16" barrel.
But I don't see any huge difference between these and 62gr fmj until I get out to 200yds or so. At 100yds I get about 1" group with 62gr, about 1 1/4" with 55gr.

 

[cfullgraf]

Bullets lighter than 50 grains probably will over spin and disintegrate when fired from a 1:7 twist barrel. 50-55 grain and up will probably work just fine but every barrel is different.

As said, the higher weight, 77 grains and up or so, bullets will be seated to longer than magazine length and will not fit in the magazine. They will work fine when loaded single shot.

When I was shooting Service Rifle Competition, some of my best 100 yard course of fire scores were with 55 grain bullets fired from a Colt Match Target gun with a 1:7 twist barrel.

 

[2ndtimer]

Bullets lighter than 50 grains probably will over spin and disintegrate when fired from a 1:7 twist barrel. 50-55 grain and up will probably work just fine but every barrel is different.

That really depends on the bullet and the barrel. While it may be true for Speer TNT 50 gr, along with Hornady 50 gr SX and Sierra 50 gr Blitz bullets (most of which were intended for .222 Remington velocities and 1 in 14” twist barrels with ultra thin jackets), I have fired lots of Nosler 40 and 50 gr Ballistic Tips, as well as Hornady V-Max and Z-Max lighter weight bullets through faster twist barrels with all bullets reaching the target and making round holes. Some of my best groups are from a Stag Model 6 AR with a heavy 24” 1 in 8” twist barrel shooting 40 gr Z-Max or Ballistic Tips.
That being said, Charlie 98’s suggestion of the Hornady 62 gr BTHP bullet from Mid-South Shooters Supply is my favorite affordable yet accurate bulk bullet. I really hope they get some in stock again someday. If the OP wants precision accuracy, he best be prepared to pay a premium price. Match level shooting sort of demands match bullets. And I don’t think anyone competes with open base FMJ bulk bullets and expects to be competitive.

 

[Charlie98]

When I was shooting Service Rifle Competition, some of my best 100 yard course of fire scores were with 55 grain bullets fired from a Colt Match Target gun with a 1:7 twist barrel.

My first AR was (is) a Colt Match H-Bar with a 1:7 barrel... it has never liked 55grn anything, we are talking 4 MOA. That's one of the reasons I wanted to try out those 62grn BTHP bullets... which turned out to be a pretty durned good bullet for the money, and has substituted the 55grn FMJ on the bench. If I'm going to take my time to load 5.56mm, I might as well use a better bullet.

Having said that, in my early years of reloading, I got very, very frustrated with reloading the 5.56mm... I could never get what I considered decent accuracy from my handloads, even hand weighing each charge and all that. It didn't dawn on me until years later, that the bullets I was using just weren't made for accuracy, or that accurate handloads with those bullets was the exception, not the rule. They did shoot a little better in my 1:8 RRA upper I picked up a few years ago.

Fast forward to the past 2 years, where market conditions had me looking at reloading 5.56mm again, coupled with 2 AR-10 builds I worked up. With the AR-10 builds, I bought the receiver lapping tool to true up the receiver extension to mate properly with the barrel... I saw how much the receiver was NOT square. After that, I started thinking more about how to improve the accuracy of my AR's, simply by pulling the barrels and lapping the receivers, and using better bullets. Wringing out that DPMS Oracle also taught me that not all AR's were built the same, either.

At the end of the day, 55grn FMJ bullets, for example, are great for MOBC accuracy (Minute of Body Cavity,) but if you want greater accuracy, even for informal shooting, you need better bullets, and perhaps some attention paid to the AR itself.

 

[mavracer]

If I'm going to take my time to load 5.56mm, I might as well use a better bullet.

If I'm gonna take the time to reload I'm using better bullets especially when we're talking pennies per 50.

 

[FROGO207]

Look at the bullets above and what might be available now and get a box of each that you might like to try. Sometimes it takes a particular brand or weight or style of bullet to make things come together. Generally the more expensive the better they shoot. I find that 65 grain and above work best in my 1:8.5 SS barreled AR.

 

[DMW1116]

I have a PSA 16” barrel with a 1/7 twist that shoots heavy bullets pretty well and light bullets pretty well. The best is the 75 grain Hornady BTHP followed by factory Frontier 55 grain 223 Remington. It has so far not done well with factory 68ish grain loads but I plan to try one in hand loads to be sure, likely the RMR 69 grain BTHP.

I say all that just to say keep trying. You’ll probably find something it can shoot, though it might be heavier or lighter than you expected. 223 bullets are less difficult to get now than a few months ago, so it might be time for a change.

 

[Reloadron]

My first AR was (is) a Colt Match H-Bar with a 1:7 barrel... it has never liked 55grn anything, we are talking 4 MOA.

Some folks manage to shoot 55 grain just fine in a 1:7 but alas I never could. Same scenario, Colt 1:7 and tried dozens of loads including match bullets and it was 4 MOA on a good day. The same rifle, off the bench, was sub MOA with heavier bullets no problem.

My advice with a 1:7 barrel is if you are going to try 55 grain I would start with a good match quality bullet and I would start with a package of 100 or less and not 500 or 1,000 bullets. With my 1:7 rifles I stick with the heavier bullets and use the light ones in my 1:12 bolt gun.

Ron

 

[DMW1116]

To specifically answer your questions, I’d say definitely try some different bullets. If you’ve only loaded the 62 grain FMJ there is a good chance there is a better shooting bullet for your barrel.

I don’t really know if you can predict the weight a barrel/rifle will like just based on twist other than longer bullets require a faster twist to stabilize. In my rifle, at 200 yards the Frontier 68 grain factory loads wouldn’t stay on the same target, but the 55 and 75 were fine.

 

[ms6852]

I do not have a 1:7 on my AR it is a 1:8 and it does not like light bullets. I use nothing but 75gr bullets, specifically the Hornady's Superformance BTHP bullets with RL15. At a 100 yards it shoots .680 5 shot groups and is sub-moa at 200 yards also. I shot a wide variety of bullets in different lengths and powders and this combination is what my AR chose. It was a long process. If it were me I would recommend loading heavier bullets that will fit your magazine without rendering your AR a single shot. If this does not work, than the barrel is the problem. Industry standard in many AR's was about 1.5"groups or more especially with the pencil type barrels.

 

[Bama59]

 

[Bcwitt]

Hornaday makes a 68 gr. BTHP that is sweet in my 7 twist.

 

[Blue68f100]

What chamber dies your gun have? If it has the Wydle chamber it was designed to shoot the heavy pills. I had one 7.5:1 twist and it would not shoot 55gr less than 2 moa. I ended up shooting the barrel out trying. Then replaced it with a Shilen 1:9 and it does wonderful. Now if you have the std 5.56 or 223R the odds are good on it be able too. Personally I would shoot in the 69gr weight and be happy. The RMR 69gr HPBT I found out from Jake that these will expand, so I will be trying these out when I round out of the 65gr SGK.