Chrome lined barrel throat dying faster vs stainless

[KZP]

Have two chrome barrels that are destroying themselves faster than a stainless. All 3 are shot under the same conditions. I don't let them get hot enough to burn my hand. Tried getting support from Barrett and their answer is semi autos have more moving parts so throat wears faster....which makes no sense to me. What is going on here?

The cracking makes it foul bad after 20 shots, have to spend hours cleaning to get back accuracy.

 

[Mike Casselton]

Mag dumps?

 

[KZP]

No mag dumps. Barrel never gets too hot to hold

 

[bfoosh006]

.50 Cal, what specific ammo ?... reloads ?

 

[KZP]

Barrels A is a mix of reloads and factory. Barrels B is all reloads. Barrel C is mix of factory and reloads. Bullets vary from. 660 ball/solids, 750 amax, 770 solids. Powder used us869, h50bmg, reloder 50. No tracers.

.50 Cal, what specific ammo ?... reloads ?

 

[Gohring65]

Interesting and noted for my barrel choices.
Two samples doing the same thing is good enough for me to not go chrome lined.

 

[bfoosh006]

Anyone know what the factory Barrett barrel is made of ? A brief search resulted in nothing helpful at all. For that matter I couldn't find ANY meaningful chamber specs etc. IE is the chamber chrome lined ... or the entire chamber and bore ?

Have you tried measuring the lands and grooves ? ( Cerrosafe ? )

I haven't seen a lot of heat cracking in barrels with such a "low" round count, does it typically start on the lands on large overbore cartridges ?... or is it more uniform, effecting the lands and the grooves at the same time ?

 

[Evintos]

Throat erosion is usually even on both lands and grooves. Barrel bore and chamber should entirely chrome lined on M107a1. Life expectancy of the barrel is minimum threshold of 1,000rds and 3,000rds life expected. It's considered burnt out if it can't maintain 3.75 inch at 100 meters.

Theoretically longer free bore means less initial throat erosion due to lower peak pressure. I would measure out the throat and see if it's shorter on the M107A1. The Cadex could be throated to load the longer 750gr projectiles compared to the M107A1 and M33 ball.

 

[Frank Green]

I've always maintained that chrome plating a bore does not mean longer barrel life as well as it can cause accuracy issues.

You can have adhesion issues with the chrome being one problem. Also when that throat starts to crack and you start losing the little chunks that can be a accuracy killer as well and I'll say when it goes it goes faster than a non chrome plated bore.

It can also effect bore uniformity which can be another cause linked to accuracy issues.

Think of this....if the chrome plating was so important in terms of accuracy and or barrel life...then why isn't it called out as a standard spec. on ammunition test barrels for the gov't? It's not on one single print that I've ever seen. I think it's a variable they don't want in the equation and if there is a problem you have another variable to look at. Also it will add costs.

In regards to accuracy test barrels for 50BMG....the accuracy barrels they get about 5k out of them (type of bullets/ammo can cause that to vary). On pressure and velocity test barrels where they have to check that and possibly along with accuracy they say barrel life is 3k rounds.

Cadex Tremor in 50cal unless they are buying barrels from another source...we make them all.

Later, Frank
Bartlein Barrels

 

[Frank Green]

Also the way the barrel is made can have an effect on barrel life as well. If it's button or hammer forged...barrel life is typically less then a cut rifled barrel.

 

[KZP]

I've always maintained that chrome plating a bore does not mean longer barrel life as well as it can cause accuracy issues.

You can have adhesion issues with the chrome being one problem. Also when that throat starts to crack and you start losing the little chunks that can be a accuracy killer as well and I'll say when it goes it goes faster than a non chrome plated bore.

It can also effect bore uniformity which can be another cause linked to accuracy issues.

Think of this....if the chrome plating was so important in terms of accuracy and or barrel life...then why isn't it called out as a standard spec. on ammunition test barrels for the gov't? It's not on one single print that I've ever seen. I think it's a variable they don't want in the equation and if there is a problem you have another variable to look at. Also it will add costs.

In regards to accuracy test barrels for 50BMG....the accuracy barrels they get about 5k out of them (type of bullets/ammo can cause that to vary). On pressure and velocity test barrels where they have to check that and possibly along with accuracy they say barrel life is 3k rounds.

Cadex Tremor in 50cal unless they are buying barrels from another source...we make them all.

Later, Frank
Bartlein Barrels

 

[Frank Green]

We we're just recently asked (like 3 weeks ago) to make a small batch to try and get better accuracy out of that platform.

As of right now it's not going to happen. Sorry brother!

The pic and caption above is pretty funny!

 

[KZP]

We we're just recently asked (like 3 weeks ago) to make a small batch to try and get better accuracy out of that platform.

As of right now it's not going to happen. Sorry brother!

The pic and caption above is pretty funny!

Too bad the barrel is such a complicated design for 3rd parties to deal with. Would be awesome to try a rifle cut stainless version.

Since this barrel is pretty much toast anyway, wondering if it's worth experimenting. Could have someone to ream out the chewed up rifling near the throat. It seems to be a fairly short area, say less than 1 inch. Or does reaming chrome lined barrels just chew it up worse? (if even possible)

 

[Frank Green]

Too bad the barrel is such a complicated design for 3rd parties to deal with. Would be awesome to try a rifle cut stainless version.

Since this barrel is pretty much toast anyway, wondering if it's worth experimenting. Could have someone to ream out the chewed up rifling near the throat. It seems to be a fairly short area, say less than 1 inch. Or does reaming chrome lined barrels just chew it up worse? (if even possible)

Trying to repair it, rechrome the bore I’ll say will be a waste of time and effort. Also the lands will get worn away under the hard chrome plating as well. So hard to fix what is gone/worn.

The other problem is getting parts. If I recall correctly they will not sell barrel extensions. You could reuse yours.

Krieger use to make them complete for Barrett while we worked there and even for a while after we left. You could try Krieger but I’ll say unless they have a order of a substantial size (not going to make one or two pieces) you would be S.O.L.

Barrett has also used button rifled barrels.

Give Krieger a call. Worth a shot. Pardon the pun there.

The other thing your dealing with is a recoiling barrel/rifle set up. So something to think about there.

 

[KZP]

The accuracy has been acceptable when the throat is in good shape, despite all the moving parts and whatnot. I've had sub 2 moa~ groups at 1k yards which is good enough for the targets I hit. Frustrating that the barrels are cooking themselves so fast for how expensive they are. Barrett recommends getting a new bolt with each barrel so after tax/shipping it's $1800 for a 29" replacement.

 

[sinister]

All barrels start to decay from the first shot.

I've seen both 5.56 and 7.62 chrome-lined GI barrels start to peel / flake at the case shoulder; throat-leade; and tops of the lands -- pretty much in the same pattern as your .50s.

Cost of doing business.

 

[KZP]

I would like to credit every single person who replied in this thread with helping me find the solution. Here is a short "how to" video. Highly recommended viewing if you plan on fixing an $1,800 barrel yourself.

 

[sinister]

Ummmkay.

Maybe not the school solution, but that certainly is A way.

You could also use something a little less aggressive-abrasive, like JB Bore Paste / cleaning compound.

 

[KZP]

Ummmkay.

Maybe not the school solution, but that certainly is A way.

You could also use something a little less aggressive-abrasive, like JB Bore Paste / cleaning compound.

JB Bore Paste isn't tough enough to deal with extra mil-spec chrome lining. This is special operations rated chrome we're talking about. Navy SEAL Army Marines require the toughest coatings. That civilian rated paste is like spitting in the wind.

 

[UpSideDown]

The true American arm has always been a .50, now finish removing that unnecessary rifling.

 

[KZP]

The true American arm has always been a .50, now finish removing that unnecessary rifling.

View attachment 7848693

On it, chief. Loading up some Tubbs super-deluxe-final-final-final-final-final finish rounds.

 

[UpSideDown]

On it, chief. Loading up some Tubbs super-deluxe-final-final-final-final-final finish rounds.

View attachment 7848704

The rifling should have always been in the bullet, not the barrel. Think you can rethread that Barret to run sewer pipe? Barrel swaps would be a breeze.

 

[Frank Green]

I would like to credit every single person who replied in this thread with helping me find the solution. Here is a short "how to" video. Highly recommended viewing if you plan on fixing an $1,800 barrel yourself.

Oh the drill and spin the rod with a polishing compound on it routine. Be careful with what you do is what I'm saying here.

If you do that with a bronze brush on the end of the rod...I'll guarantee damage to the bore. Chrome plated or not.

Either way I won't do that to any of my sticks.

I'm ok with JB bore compound and Rem. 40x cleaner. Haven't used bumper polish ever...so no comment on that.

 

[Frank Green]

from the OP's original post.... "semi autos have more moving parts so throat wears faster"

That's a new one to me!

 

[brianf]

it truly amazes me what people will do to barrels

add to that they think it actually works...... which is a whole different ball of wax to get into


its really not that hard:

dont overcook it when shooting if you dont have to

clean it regularly

use quality products

 

[KZP]

it truly amazes me what people will do to barrels

add to that they think it actually works...... which is a whole different ball of wax to get into


its really not that hard:

dont overcook it when shooting if you dont have to

clean it regularly

use quality products

Those 3 barrels are from slow strings of 3 to 5 depending on ambient conditions then long cool down. Cadex barrel looks great, both Barrett are crunchy. Each barrel gets 25 to 50 shots per session then cleaned with boretech products.

I'm surprised the satire wasn't obvious enough when I used carbide lapping compound on a drill at high speed. Maybe I should use a die grinder next time. That barrel is a waste of ammo to shoot before it got " fixed".

 

[brianf]

Those 3 barrels are from slow strings of 3 to 5 depending on ambient conditions then long cool down. Cadex barrel looks great, both Barrett are crunchy. Each barrel gets 25 to 50 shots per session then cleaned with boretech products.

I'm surprised the satire wasn't obvious enough when I used carbide lapping compound on a drill at high speed. Maybe I should use a die grinder next time. That barrel is a waste of ammo to shoot before it got " fixed".

Not pointed towards you in general…shit barrels are shit barrels.

I was more generalizing the other 20 posts a day of guys doing dumb shit to barrels

 

[knuckleballz]

Shooting solids will cause shorter barrel life. I would only shoot solids in a rifle that is easy to rebarrel. Only expect 1000 rounds or less until accuracy goes away. Based on my experience, lots of variables involved.

 

[brianf]

Shooting solids will cause shorter barrel life. I would only shoot solids in a rifle that is easy to rebarrel. Only expect 1000 rounds or less until accuracy goes away. Based on my experience, lots of variables involved.

what solids do you shoot etc

thanks

 

[bfoosh006]

Shooting solids will cause shorter barrel life. I would only shoot solids in a rifle that is easy to rebarrel. Only expect 1000 rounds or less until accuracy goes away. Based on my experience, lots of variables involved.

I can't help but wonder if the solids are causing "early / accelerated" wear at the lands.
Clearly something was causing the lands to heat up before the grooves, and I would think the added friction from the "not readily compressible" solids is possibly part of the issue.

Did all 3 barrels get solids fired through them ?

 

[KZP]

I can't help but wonder if the solids are causing "early / accelerated" wear at the lands.
Clearly something was causing the lands to heat up before the grooves, and I would think the added friction from the "not readily compressible" solids is possibly part of the issue.

Did all 3 barrels get solids fired through them ?

Barrel B is 50/50 on solids to jacketed, Barrel A had about 100 solids total, rest were copper jacket. Cadex barrel C is 90% solids.

 

[bfoosh006]

Barrel B is 50/50 on solids to jacketed, Barrel A had about 100 solids total, rest were copper jacket. Cadex barrel C is 90% solids.

Well... that blows my feeble train of thought out of the water. Lol

While I realize overbore rounds will erode barrels faster, and erosion starts from day one... I wouldn't be happy with Barrets barrels performance so far.
If the erosion was in the grooves as well, I would understand that more... but just the lands seems odd to me.

That was one of the reasons I asked about the land and groove measurements... is it possible, the lands are over / undersized and are being exposed to greater erosion ?

Anyone have any speculation as to why just the lands on the Barret barrels ?

 

[Frank Green]

Well... that blows my feeble train of thought out of the water. Lol

While I realize overbore rounds will erode barrels faster, and erosion starts from day one... I wouldn't be happy with Barrets barrels performance so far.
If the erosion was in the grooves as well, I would understand that more... but just the lands seems odd to me.

That was one of the reasons I asked about the land and groove measurements... is it possible, the lands are over / undersized and are being exposed to greater erosion ?

Anyone have any speculation as to why just the lands on the Barret barrels ?

The lands in the bore of the barrel stick up. So they take the brunt of the beating...either from shooting or cleaning! So they will show the damage/wear the soonest.

For a even numbers sake on a 50cal barrel your looking at a .500" bore x .510" groove. So each land is only .005" tall. Not much more than the thickness of a human hair.

A 6mm barrel with a .237" bore x .243" groove...each land is only .003" tall.