6br shot out at 1200 rounds

Mod 12 with aftermarket prefit barrel. Using Varget 30.2gr, 105 hybrid's at 2900fps. Worked out to 1000 yards on steel targets. Barrel was never abused. Max 4-5 shots before a cool down, commonly with a chamber chiller. Standard results were cloverleaf at worst at 100 yards. Suddenly went to 2MOA. Teslong borescope shows firecracking, and burring at the beginning of the leade. I've never used an abrasive in the throat of a barrel. Assuming I try using an abrasive to clean up the throat, how many more shots can I realistically expect from this barrel? Numbers I've seen lead me to believe that 1200 rounds is low by 700-800 shots. But, it is what it is. I've got a Shilen from Jim that's been sitting around for a while, ready to be installed. Based on experiences, should I just put the Shilen on, and forego the abrasives?

Got nothing to lose at this point and a backup barrel. Give it a try and see if it helps. It should definitely last longer than 1000.
Have you checked your distance to lands yet and compare it to when you did your original load developement? Just to see how much the throat is worn?
Reason I ask is I just had a factory 22/250 barrel that opened up groups on me. Not 2moa but still 2x what it was. I scrubbed the crap out of it, especially the first 6-8” of the bore where the firecracking was, using a chamber rod and a 6.5cal brush. Afterwards rechecked my distance to lands and it was .030” farther than when I did my load development a couple years prior. That barrel has 1600 rounds on it.
So I seated my bullets out .030 farther and used same load. Just took it back to the range last week and shoot 2 groups in the .3’s and a 7 shot group in the 4’s… not sure how long it’ll last but it made it a lot better.

Should have started out with zero free bore and 40s/50s but it's too late now. Plan ahead. ;)
Started out with a long throat (off the shelf chamber) but couldn't reach the lands. I went custom chamber from then on.
Found someone that wanted to shoot heavies so I sold him that barrel and got myself a short throat. Both of us were happy. :cool:

I have not seen as bad a change, but, mine slowly opened up to more than 1/2MOA over about 1000rnds. Finally the light bulb went off and I loaded some a little longer and voila! Back to smaller groups. I'm using the 103gn Vapor Trail machine made bullets.

You can have the chamber/throat reamed, & set back.

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Originally Posted by MS50

105 hybrid's at 2900fps. Barrel was never abused.

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I don't think that both of these things can be true. While 2900 fps isn't out of the ordinary for what you read online- it is still abusing the barrel. Lots of people shoot at that bullet/velocity combo- but the result is less barrel life. Most reloading data (companies with pressure testing equipment) shows around 2700 to 2750 max velocity.... and the Norma factory ammo (only factory ammo that I'm aware of) is around 2650 fps with a 105 grain bullet.

That last 100 fps that we all want to get can do some crazy things- such as cutting a barrels life in half..... sometimes it's worth it- other times its not.

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Originally Posted by Whynot

I don't think that both of these things can be true. While 2900 fps isn't out of the ordinary for what you read online- it is still abusing the barrel. Lots of people shoot at that bullet/velocity combo- but the result is less barrel life. Most reloading data (companies with pressure testing equipment) shows around 2700 to 2750 max velocity.... and the Norma factory ammo (only factory ammo that I'm aware of) is around 2650 fps with a 105 grain bullet.

That last 100 fps that we all want to get can do some crazy things- such as cutting a barrels life in half..... sometimes it's worth it- other times its not.

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Well said.

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Originally Posted by Whynot

I don't think that both of these things can be true. While 2900 fps isn't out of the ordinary for what you read online- it is still abusing the barrel. Lots of people shoot at that bullet/velocity combo- but the result is less barrel life. Most reloading data (companies with pressure testing equipment) shows around 2700 to 2750 max velocity.... and the Norma factory ammo (only factory ammo that I'm aware of) is around 2650 fps with a 105 grain bullet.

That last 100 fps that we all want to get can do some crazy things- such as cutting a barrels life in half..... sometimes it's worth it- other times its not.

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I hear what you're saying, and it's true. My friends and I have talked about this recently. I believe that shooters that are doing well with their 6mm's and 223's at 1000 yards are burning barrels. I take very few shots at 900/1000 yards. Most shots are between 200 and 700 yards. A lower energy level will work well at those distances. I'll work on the throat of this barrel and use the reloads I have left to see what happens. Thanks to all for the feedback.

I had a Shilen 4R barrel for my 6BR Savage, mostly shot in 600 yard competitions. 30.0 gr Varget with a Berger 105 Hybrid. was a tack driver got a little over 2500 rounds before I started getting flyers. Have a brand new barrel sitting in the safe waiting to be put on.

105's @ 2900 fps is right there with what the 6mm Creedmoor does with 108's @ 2900 fps. Most of those barrels are toast after 1200-1500. The 6 Creed is known to be a barrel burner...

30gr Varget and 105 class bullets is a 6br "gold standard". The reality is that the throat in my barrel is a mess. I've considered trying VV powders as they allegedly burn cooler. I'll scrub the throat and see what happens before re-barreling. My current reloads are seated at .005 off the lands. Testing earlier this year, I found a flat spot in performance between .060 and .075 off the lands. Depending on wear, they may just work out. Thanks for the feedback, always good to learn something.

I'm using 103gn bullets and 29.8gn of Varget for my 1000yd shooting. 2900fps in a 26" barrel. I don't compete. I've also run 28.0gn at 2780fps when I am shooting less than 500yd. That bullet likes to be in the lands.

2900 fps isn’t terribly out of line for a 6 BR, most run low to mid 2800’s with a 105 class bullet. I have gotten just over 2000 rounds and buddies have gone further without accuracy drop off’s. I clean older barrels very aggressively with bronze brushes and follow up with Iosso paste. If your accuracy drops off I would also look at seating depth variances and re-tune when needed.

Being the Shilen is my first custom barrel I have been kinda afraid to get too aggressive with cleaning. I do use the bronze brush a bit, but, not half as much as I do with my Savage barrels. So far I've been able to keep it clean (at least looking at the muzzle rifling). The throat is probably not as clean as it should be.

I sometimes wonder if I’m cleaning too much, so just for conversation let’s say aggressive cleaning did result in some lost round count and I’m not talking about brushes attached to drill motors or lapping beyond cleaning paste, just solutions and bronze or nylon brushes with many stokes and plenty of soak time.
How many rounds are we losing and of what quality are these rounds towards the end of the competition barrels life ? I think having 1200 or 2000 really good rounds is better than 500 extra subpar rounds out of the same barrel. At the end of the day barrels are consumable components are they not ?

Indeed

Yes, they are. I am about to order a new barrel for the 6BR. I figure by the time the backlog is cleared I'll need to replace mine.

I agree that a good cleaning is needed every now and then. I usually clean every 100 rounds. Just was curious. I've seen folks run the gamut from cleaning a lot to some who won't put a brush through a bore, just solvent and patches.

I suspect all the caution about cleaning is due to the folks who don't shoot much, but, clean aggressively after each 5 or 10 rounds of ammo. Or the guys who use stainless brushes, or seesaw a boresnake.

Oh yeah… don’t worry about cleaning. I clean my firearms incessantly! Can’t hurt it the way you described. It’s steel! Here’s a little test for you. Take a piece of Carbon or Stainless steel. Use a scribe to make a good scratch in the steels surface. Then clean it everyday in the same fashion you would clean your barrels. Clean it TWICE what you would the barrel every day for a month. Then tell us if the scribed scratch has changed at all. Or I can save you the time because it won’t! LOL!

No, neither the throat nor the land/groove can be worn away from normal cleaning. Not with approved cleaning solution, using plastic/bronze brushes, inside even 3000+ rounds. Now, using acidic solution or with steel brushes & maybe 20,000 rounds; well, that’s a different story.

I don't disagree.

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Originally Posted by MS50

30gr Varget and 105 class bullets is a 6br "gold standard". The reality is that the throat in my barrel is a mess. I've considered trying VV powders as they allegedly burn cooler. I'll scrub the throat and see what happens before re-barreling. My current reloads are seated at .005 off the lands. Testing earlier this year, I found a flat spot in performance between .060 and .075 off the lands. Depending on wear, they may just work out. Thanks for the feedback, always good to learn something.

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I would clean it well and stop using the bore scope to judge barrel life, let the target do the talking. Setting back a chamber is a option if you have your own reamer and get a good deal from your gunsmith or do it yourself, otherwise a set back can run the same price as new plus no one likes using their sharpe reamer on your old chipped up throat. I figure some smiths will, but who wants to be the next customer using that set back reamer ?

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Originally Posted by charlie b

I have not seen as bad a change, but, mine slowly opened up to more than 1/2MOA over about 1000rnds. Finally the light bulb went off and I loaded some a little longer and voila! Back to smaller groups. I'm using the 103gn Vapor Trail machine made bullets.

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This^

Besides the throat eroding over time, so is the leade. That leade must be perfect to the
rifling. If it does not erode evenly, which it wont, the engraving will be uneven and will
effect accuracy....And don't forget the crown. I'll normally re-crown 2 more times over the
life of a barrel I compete with.

How far back do you cut a crown, or is it just enough to 'ream' the crown to refresh the edges?