243 barrel life

[Howard Roark]

He was changing the barrels between 700 and 800 rounds!

Ha, he also loaded every round like he was shooting for the Leech Cup!

Shooting lighter bullets a bit on the slower side at the 200 & 300 yard lines and saving the 107s for the 600 extends barrel life. Moly also extends barrel life. I get 2500 rounds and better on Bartlein .243 barrels before they show signs of deterioration.

 

[JO JO]

so what is better 100gr at 2500 fps or lighter at higher fps
slow or fast powders to extend life

 

[Bart B.]

I get 2500 rounds and better on Bartlein .243 barrels before they show signs of deterioration.

That's a typical remark by high power match rifle competitors ranked as marksmen shooting the lowest scores. The high master classified ones winning and setting records say they slowly get worse from new to about 1500 rounds which is when their .243 Win accuracy degrades about 50%. 'Tis like the ones shooting 30-06 and 308 Win claiming 7000 rounds of barrel life before they feel the barrels are worn out. 3000 rounds is the typical limit for the winners and record setters.

I don't think any centerfire barrel keeps the same level of accuracy over 2300 rounds. All the bullet makers I've talked with about barrel life say they slowly shoot bigger average groups. Sierra's barrel life point is when a barrel starting out about 1/4 MOA average gets to about 3/8 MOA average as tested with a reference lot of super accurate bullets called "standards." That's a 50% accuracy loss.

All that aside, we all have our own barrel life rubber ruler and we can stretch it as much as we want so the actual spacing between its inch marks is whatever we like.

 

[Howard Roark]

That's a typical remark by high power match rifle competitors ranked as marksmen shooting the lowest scores. The high master classified ones winning and setting records say they slowly get worse from new to about 1500 rounds which is when their .243 Win accuracy degrades about 50%.

I'm not so sure that this is a fair statement, and it's a little condescending.

Of course barrels lose accuracy over their life span. The question is what is acceptable accuracy for the owner.

There is a member on the Sierra team that has won the RNDC twice that shoots a .243 that has done quite a bit of testing over the years on this subject. His and my experience show that acceptable high master accuracy can be more than some get or will believe can be attained when moderate short line loads and moly coating are used.

 

[Bart B.]

Of course barrels lose accuracy over their life span. The question is what is acceptable accuracy for the owner.

A much better comment than

I get 2500 rounds and better on Bartlein .243 barrels before they show signs of deterioration.

What's your start accuracy (average group size) and what's the percent of degradation when you decide it's time to rebarrel because it's no longer acceptable?

Most I've discussed this with say starting at 1/4 to 1/3 MOA through 200 yards (maybe 1/2 at 300) then degrading 50%. That's with max loads and maybe 40% of them no more than 10% reduced. Any more reduction causes case headspace problems and leads to head separation.

 

[Art Eatman]

Bart, I'm aware of the burning of the leade. My question from ignorance is, Is there accuracy degradation in the barrel's rifling on beyond the leade?

 

[Bart B.]

Art,

Yes, there's erosion past the leade (throat?) or whatever you call the angled rifling from freebore diameter down to bore diameter. It's not as much as on the angled rifling. And there's usually more in the bottom half of the barrel 'cause that's where the powder and primer residue settles. It acts as a lapping compound as following bullets press then rub it against the barrel steel. All of which means bullets won't shoot as accurate after some amount of erosion. Sometimes it can be seen as a dark area at the bottom of the chamber at the origin of the rifling compared to the area at the top which is brighter.

Some folks cut the chamber off at its mouth on a barrel that's about 3/4ths worn out then reshank and rechamber it. The reamer takes out nearly all of the erosion. That barrel will now last about 80% as long as it did originally.

And some will repeat this all over again. Starting out with a 30" barrel is a boon to such adventures.

 

[Howard Roark]

Most I've discussed this with say starting at 1/4 to 1/3 MOA through 200 yards (maybe 1/2 at 300) then degrading 50%.

My expectations and observations pretty much mirror this but the shooter has to be taken into account as well. 1/3 MOA on the bench is not 1/3 MOA on the target.

The hardest holders out there hold ¼ MOA day in and day out. They can call their shots on the figure (X) in good conditions. Personally, I’m a low high master shooter and can only hold about ½ MOA. I’m happy to accurately call where in the x-ring my shot breaks. So, a rifle that starts out shooting 1/3 MOA on the bench and then shot by the best sling shooter actually is just over a ½ MOA rifle on the target.

If there is anyone out there who actually bench tests their rifle at any time after initial load development and testing I’ve never heard of it. What most people rely on is noticing when shots begin to go outside of call. How far outside is too much is determined by the shooter and those who are winning and setting records don’t allow much.

Supported shooters like the Army/Marines who have extensively tested barrel life pull them before they have a chance to show degradation. As soon as 1200 rounds on a .223. All their brass is new, shot once and is loaded with the mindset of getting to the target as fast as possible. They go the line every time with a barrel that’s in its prime. Those who shoot on their own dime, even the big boys and girls don’t do that for fiduciary reasons.

Getting the most out of any barrel while maintaining accuracy just makes sense. Shooting an 85/90 gr bullet at moderate speed clearly reduces stress on the bore. I could drive every round at the 200 & 300 yard lines beyond 3100 fps. But why? 2840 fps works just fine. It makes sense to push harder at big matches but not all the time. 75% of every regional match course is shot on the short lines. By burning 4 grains (10%) less than max powder charge and thereby lowering chamber pressure by 8000-9000lbs (20%) throat erosion is reduced for 75% of the rounds fired over the life of the barrel.

 

[redbullitt]

My buddy has one thats been a deer rifle for at least 25 years. Still shoots around 1.5 inches at 100 yards.

Has to be over 1000 rounds though it, as I have shot probably 250 through it myself.

Sure wallops the deer around here lol.

 

[Bart B.]

The hardest holders out there hold ¼ MOA day in and day out. They can call their shots on the figure (X) in good conditions

I don't believe anyone holds that tight and calls that precise. In my chats with those doing the best, score wise, they hold 1/2 to 5/8 MOA and get most of their shots off inside 1/4 to 1/3 MOA; in calm winds.

However, if there is, they'll win most of the matches and set most of the records if their stuff (gear and marksmanship skills) are up to the task. To date, nobody's kept all their record shots inside 2 MOA at any range; up to 20, once in a great while, but not all of them in every match.

How 'bout some names, please?