308 Slow barrel help???

[ryguy00]

Ok, I've got a 308 built on a Remmy LA with a pre chambered shilen 1:10 shooting 175gr vld's. Starting loads are around 2300 with max around 2600 in the berger book. I'm using Lapua brass and Varget and have pushed them all the way up to 2950 before getting pressure signs, however, they just will not freaking shoot at any respectable speed. Backing them down to low-mid 2200's has them grouping in the .4's and .3's which is the accuracy I need for my intended use. That's absurdly slow though! Anything faster and groups open to 3/4-1 MOA which is not good enough. Now I've heard of "slow barrels" before, but is this "normal" for a slow barrel to be THAT slow???

Yes, I'm aware that changing bullets and bullet weights will bypass this problem, and I plan to do so, but I'm just baffled by this.

 

[eric32]

Have you tried to play with the seating depth? With the proper VLD stem in place. Also you might just have a really finicky barrel.

 

[ryguy00]

Have you tried to play with the seating depth? With the proper VLD stem in place. Also you might just have a really finicky barrel.

Yes, I've done the vld length test. 3 separate times actually. These bullets like a long jump. .110 off the lands. I've played all around that area and as long as I keep it at 2220-2250 it's singing. Any faster and it goes to hell immediately. I know that the hottest loads are rarely the most accurate, but I never expected to be BELOW the starting loads!

 

[eric32]

Well just might be one of those barrels theead the muzzle and strap a supressor to and make it your quiet rifle

 

[ryguy00]

Well just might be one of those barrels theead the muzzle and strap a supressor to and make it your quiet rifle

Well, it's currently on a benchrest/varmint rifle and is threaded for a brake, however, with my disappointment with the 308 caliber in general, it's getting rebarreled to 6.5x284. The 308 barrel is going onto a tactical build in progress that will be used strictly for steel out to 600 yds. At that point, it's getting cheaper lighter bullets, and I'll be using one of my cans on it.

Still though, is this a common thing to have happen? I suppose I can't blame the barrel solely. The barrel will give the velocity I want, just not the accuracy at that velocity, which points more to the bullets. The bullets are accurate, as long as they're going slow. I guess I never imagined needing to download a 308 to 30-30 speeds to get any accuracy from it. But then again, I went into this blind enough to think it would make a good 1k prairie dog caliber. I've learned a lot....

 

[eric32]

That to me seems like a flier barrel when i hear the barrel speeds you are getting. Never honestly heard of one that slow before. But try another bullet or maybe clean the barrel really well and try agian.

308win is a a all round great caliber. I just finished my new load today using 4064 and the new 168gr TMK at 2700fps pretty awesome. 10.3 mils to get to 1k cant really go wrong there

 

[ryguy00]

That to me seems like a flier barrel when i hear the barrel speeds you are getting. Never honestly heard of one that slow before. But try another bullet or maybe clean the barrel really well and try agian.

308win is a a all round great caliber. I just finished my new load today using 4064 and the new 168gr TMK at 2700fps pretty awesome. 10.3 mils to get to 1k cant really go wrong there

Well, at 2200, it's not throwing any fliers. It's shooting 5 shot groups in the .3's and .4's. Above 2200, I wouldn't even call it "fliers" so much as "patterning like a shotgun" Some people would be thrilled with 3/4-1 MOA but for me, it's not even worth owning. As I've said above, this is a benchrest type rifle. It gets cleaned every 25 rounds. Yes, you can lob it to 1k, but not with the accuracy I need for prairie dogs. For tactical use, it's ok, but a 300 win would still be better. I honestly don't understand the hype over the 308. There are tons of better choices. But that's completely beside the point of my problem.

 

[ZenArchery]

Contact Phil @ Berger Bullet co. He will steer you right direction.
What is your barrel twist?
You are in a conundrum of sorts. If you want accuracy keep it at 2200 fps. At least that's what I would do.
If you want speed find a lighter bullet.
Banging steel out to 600 yards with a .3 to .4" accuracy. I wouldn't change anything.

 

[jsthntn247]

Get a box of Juggernauts and load them .015 off the lands from 43-44.5gr of Varget. If they won't shoot you have a bad barrel.

 

[JasonT]

To me (I'm not an expert), it sounds like the barrel's bore has some rough surfaces and pitting that are catching the copper jacket and stripping layers off of parts of the bullet. This "stripping" action is uneven and results in a bullet with a damaged center of gravity. This could lead to unexpected excess spin drift. I've seen this problem happen at barrel-burner speeds like 2900-3000fps, but disappear at lower speeds. It's also possible that the throat has a pretty gnarly burr on one of the lands from potentially sloppy chambering.

If you've cleaned your barrel with a good bore cleaner like Montana Extreme 50BMG, Boretech Eliminator, or Sweets 7.62, and that didn't help, then check the muzzle end with a caliper to find the groove/bore diameter. If the bore diameter (on the lands) is between 0.298 and 0.301, then you're good. The groove diameter should be somewhere between 0.307 and 0.309. These are pretty wide ranges, but they're guidelines a wise old man once taught me.

If all else fails, try wrapping a slightly undersized (7mm) stiff nylon brush with a bunch of patches and coating it in JB, Iosso, or Flitz. Run that up and down the barrel (not out the muzzle though) until you feel like the barrel has been adequately polished. If that doesn't work, then you really do have a bad barrel that needs replacement.

The good news is that you can now get Remage barrels for not much more than a normal barrel blank. They use a savage-style nut so you can swap your barrel at home. I think Criterion makes them.

My $0.02

 

[ryguy00]

Contact Phil @ Berger Bullet co. He will steer you right direction.
What is your barrel twist?
You are in a conundrum of sorts. If you want accuracy keep it at 2200 fps. At least that's what I would do.
If you want speed find a lighter bullet.
Banging steel out to 600 yards with a .3 to .4" accuracy. I wouldn't change anything.

Barrel is a 1:10. And remember, we're talking about the same barrel but two different rifles. Currently it's on a benchrest/prairie dog rifle. Accuracy is most important.

When I change this rifle to 6.5x284, I'm putting this 308 barrel onto a different rifle for tactical/steel, and will be switching to lighter bullets then even if accuracy suffers at that point.

As it sits for prairie dogs, I limit this rifles distance because accuracy falls apart around 600 yds and I usually switch to a different rifle for beyond 600 yds. I don't think the velocity loss will hurt me too much at that distance. We'll see what the wind does....

 

[ryguy00]

Get a box of Juggernauts and load them .015 off the lands from 43-44.5gr of Varget. If they won't shoot you have a bad barrel.

I think you're completely missing my question. I never said this barrel was bad, just that it won't shoot accurately enough for me at the velocity I want.

 

[ryguy00]

To me (I'm not an expert), it sounds like the barrel's bore has some rough surfaces and pitting that are catching the copper jacket and stripping layers off of parts of the bullet. This "stripping" action is uneven and results in a bullet with a damaged center of gravity. This could lead to unexpected excess spin drift. I've seen this problem happen at barrel-burner speeds like 2900-3000fps, but disappear at lower speeds. It's also possible that the throat has a pretty gnarly burr on one of the lands from potentially sloppy chambering.

If you've cleaned your barrel with a good bore cleaner like Montana Extreme 50BMG, Boretech Eliminator, or Sweets 7.62, and that didn't help, then check the muzzle end with a caliper to find the groove/bore diameter. If the bore diameter (on the lands) is between 0.298 and 0.301, then you're good. The groove diameter should be somewhere between 0.307 and 0.309. These are pretty wide ranges, but they're guidelines a wise old man once taught me.

If all else fails, try wrapping a slightly undersized (7mm) stiff nylon brush with a bunch of patches and coating it in JB, Iosso, or Flitz. Run that up and down the barrel (not out the muzzle though) until you feel like the barrel has been adequately polished. If that doesn't work, then you really do have a bad barrel that needs replacement.

The good news is that you can now get Remage barrels for not much more than a normal barrel blank. They use a savage-style nut so you can swap your barrel at home. I think Criterion makes them.

My $0.02

Being a benchrest type rifle, I clean every 20-25 rounds with butches and sweets. I've scoped the bore and it looks like a brand new barrel. It only has about 600 rounds on it since new and I cannot measure any throat erosion at all. Jam length is still right where it was new. That being said, your point is well taken. That could make sense if something was throwing the balance off.

Judging by the accuracy at the slow speeds, I hesitate to say the barrel is bad. It does shoot well, just at disappointing speeds with my chosen bullets. However, I suppose if it'll shoot a different bullet faster with good accuracy, then that means the problem was my bullets and not the barrel afterall. Truth be told, I'm just about out of these bullets anyway. Might as well switch weights before continuing but I'm not touching it until I get back from the prairie dog hunt. All of my brass is loaded and ready to go.

 

[people]

You never know any of your components could be causing issues as you know. If you cared to work it more trying different powder and primers may be in order.

Granted your rifle may just not like those bullets.

 

[ryguy00]

ZenArchery: By the way, I took your advice and fired off an email to Berger tech support. I'm not sure if it'll find its way to Phil or not though.

 

[ryguy00]

Update: The email did indeed reach Phil. He has replied, we've clarified a few things, and I'm awaiting his next reply

 

[walt willis]

Ok, I've got a 308 built on a Remmy LA with a pre chambered shilen 1:10 shooting 175gr vld's. Starting loads are around 2300 with max around 2600 in the berger book. I'm using Lapua brass and Varget and have pushed them all the way up to 2950 before getting pressure signs, however, they just will not freaking shoot at any respectable speed. Backing them down to low-mid 2200's has them grouping in the .4's and .3's which is the accuracy I need for my intended use. That's absurdly slow though! Anything faster and groups open to 3/4-1 MOA which is not good enough. Now I've heard of "slow barrels" before, but is this "normal" for a slow barrel to be THAT slow???

Yes, I'm aware that changing bullets and bullet weights will bypass this problem, and I plan to do so, but I'm just baffled by this.

Question: Is yours a semi auto or bolt action? Dynamic resistance is motion increased as the speed goes up. try cleaning and treating the bore with NuFinish car Polish and recheck your FPS again.
Do not use a lub as it will cause problems in two ways. Un burnt powder is of carbon and will cause early wear and also higher pressures.

 

[ZenArchery]

Update: The email did indeed reach Phil. He has replied, we've clarified a few things, and I'm awaiting his next reply

Yep. Phil's the man! I had one goal. 2 trips to the range later. Goal was achieved. Saved me a lot of time, energy, and resources. They know their bullets. They know its potential to operate in the platform you set up. Best part is they are a GREAT knowledge base and INCREDIBLE communicators of their product.

BTW Sent email to Berger 2 weeks ago. Still haven't had a reply...

 

[walt willis]

I think you're completely missing my question. I never said this barrel was bad, just that it won't shoot accurately enough for me at the velocity I want.

What you want may not be what your gun wants?
There is a way to have both, but it may require that you crown and shoot until you find the sweet spot closer to the speed you are looking for.

 

[barefooter56]

Yep. Phil's the man! I had one goal. 2 trips to the range later. Goal was achieved. Saved me a lot of time, energy, and resources. They know their bullets. They know its potential to operate in the platform you set up. Best part is they are a GREAT knowledge base and INCREDIBLE communicators of their product.

BTW Sent email to Berger 2 weeks ago. Still haven't had a reply...

ZenArchery,
Please resend the email and address it to me. It will be taken care of immediately. techsupport@bergerbullets.com
Our apologies for this.