.243 vs .243AI vs 6mm Rem barrel life?

M

mattri

Member
Which of these rounds is going to give the longest barrel life in general?

Obviously a lot of things will determine throat erosion/barrel life. Assuming shooting at a reasonable rate with simmilar loads which round will be the easiest on barrels?
 
mattri

They are all about the same and you'll be hard pressed to tell any difference in barrel life. But - the straight 243W has the smallest case capacity, therefore uses less powder, therefore it should be easiest on a barrel.

Ray
 
the plain 243win might get another hundred rounds of life from a barrel. the 243AI and 6mm rem should have practically the same lifespan.
 
Thanks for the replies. I've heard a lot of conflicting info on this:

The .243 Win uses the least amount of powder, therefore gives the longest throat life.

The .243 Win, with it's 20* shoulder and short neck will burn barrels faster than the others.

The .243 AI is overbore and will eat barrels.

The improved shoulder of the .243 AI will prevent more of the corrosive gasses/heat from the throat and prolong barrel life.

The 6mm Rem uses the mot powder and will eat barrels the fastest.

The longer neck of the 6mm Rem makes it the best suited for long barrel life.

These are the things I've been finding as answers to this question. I understand that the harder you push a round, the faster you shoot, etc will erode throat life. Not looking to re-invent the wheel or get maximum velocity at no cost, just trying to find some objective comparisons between these three rounds.

Thanks again, Matt.
 
Objective comparison is this....

Barrel wear is mainly the result of ablation.

Ablation is driven by temperature over time.

Generally a larger case will burn more powder over a longer period of time.

Neck length, shoulder angle "Turbulence Point Theory" etc have nothing to do with it.

IMO

al
 
I certainly do "Not" claim to be any expert on the theory of barrel mechanics or on barrel life, and I will leave the discussion of that theory to those better informed to speak to that issue. I do know about the barrel life in my rifles. I have a orginal model 1885 Whinchester Highwall Single Shot rifle that I have shot High Power silhouette with for years. This rifle was orginal chambered in 45-70, I rechambered it into 6MM Remington when I first got it. I had a full Octagon barrel installed at 30" long. That barrel lasted exactly two seasons of Silhouette. I shot a Match twice a month for the most part and three times a month sometimes. A course of fire was 40 shots for record plus unlimited sighters and I usually shoot 4 or 5 sighter shots per animal. That would be a total per match of 60 shots. I then shot at least two practice sessions a week and for the most part that was 50 shots per session. My rough math says that was a total around 2,100 rounds down the tube for two years for a total of 4,200 total rounds before that old Highwall just stop shooting. I then sent the rifle to Hart for one of the barrels, once again I put a heavy profile 30" barrel, 1.125 round with no taper. That barrel has been on the rifle now for four years, it still shoots as it did the day I got it back from Hart, it has had at least 9,000 or maybe 10,000 rounds down the tube. My silhouette load is "Not" a hot load per say it is designed to shoot Silhouette and that calls for an Honest 2 MOA bare min rifle from 200 meters to 500 meters. This rifle has always shot fairly better than that 2 MOA but to be honest it shoots around 1 MOA on most days off hand. On a good day from the bench it may shoot 3/4 MOA.

Is this the normal barrel life span of a 6MM barrel? I don't have a clue about that, but is what this Hart 6MM barrel has done so far.......

Roland
 
One factor that can make comparisons of barrel life difficult is powder selection. Double base powders generally have higher flame temperatures, that can make barrels go away faster. Rate of fire is also a significant variable, and I think that peak pressure plays a role as well.
 
mattri said:
Thanks for the replies. I've heard a lot of conflicting info on this:

The .243 Win uses the least amount of powder, therefore gives the longest throat life.

The .243 Win, with it's 20* shoulder and short neck will burn barrels faster than the others.

The .243 AI is overbore and will eat barrels.

The improved shoulder of the .243 AI will prevent more of the corrosive gasses/heat from the throat and prolong barrel life.

The 6mm Rem uses the mot powder and will eat barrels the fastest.

The longer neck of the 6mm Rem makes it the best suited for long barrel life.

These are the things I've been finding as answers to this question. I understand that the harder you push a round, the faster you shoot, etc will erode throat life. Not looking to re-invent the wheel or get maximum velocity at no cost, just trying to find some objective comparisons between these three rounds.

Thanks again, Matt.
Click to expand...

I gotta dissagree with you!

* the .243 Win. is a poorly designed case from the start. The neck's way too short, and barrel life is well known to suffer

*.243AI is a better designed case by having the 40 degree shoulder angle, but once again the neck is still too short for long heavy bullets and extremely short ones as well

*6mm Remington has a much longer neck, helping to keep the turbulence point out of the throat. Meaning a greater barrel life.

Now the case capacity of both rounds is not that far apart, and Ackley stated that he felt the 6mm case capacity to be about max without going overbore. To take this further, most max loads between these two rounds are usually within 2 or 3 grains of powder (5% roughly). I know more than one person that got less than 800 rounds out of a .243AI barrel, and also a good many that got less than 1200 rounds out of their .243 barrels. Yet I've seen many guys shooting plain jane 6mm's get over 2,000 rounds out of C/M barrels, and still shoot nice tight groups. Now I shoot the 6/250AI a lot. It has slightly less powder capacity than the .243, but is still hard on barrels (neck's too short). Gun still groups in the threes, but I also know it's only a matter of time. My next chamber will be the 6/250AI, but reamed with a 6mmAI reamer for the longer neck. Also have plans to build a 6BG in the near future, as I think this round better suits my needs (I'm not exactly in love with the 40 degree shoulder)
gary
 
Hombre0321 said:
I certainly do "Not" claim to be any expert on the theory of barrel mechanics or on barrel life, and I will leave the discussion of that theory to those better informed to speak to that issue. I do know about the barrel life in my rifles. I have a orginal model 1885 Whinchester Highwall Single Shot rifle that I have shot High Power silhouette with for years. This rifle was orginal chambered in 45-70, I rechambered it into 6MM Remington when I first got it. I had a full Octagon barrel installed at 30" long. That barrel lasted exactly two seasons of Silhouette. I shot a Match twice a month for the most part and three times a month sometimes. A course of fire was 40 shots for record plus unlimited sighters and I usually shoot 4 or 5 sighter shots per animal. That would be a total per match of 60 shots. I then shot at least two practice sessions a week and for the most part that was 50 shots per session. My rough math says that was a total around 2,100 rounds down the tube for two years for a total of 4,200 total rounds before that old Highwall just stop shooting. I then sent the rifle to Hart for one of the barrels, once again I put a heavy profile 30" barrel, 1.125 round with no taper. That barrel has been on the rifle now for four years, it still shoots as it did the day I got it back from Hart, it has had at least 9,000 or maybe 10,000 rounds down the tube. My silhouette load is "Not" a hot load per say it is designed to shoot Silhouette and that calls for an Honest 2 MOA bare min rifle from 200 meters to 500 meters. This rifle has always shot fairly better than that 2 MOA but to be honest it shoots around 1 MOA on most days off hand. On a good day from the bench it may shoot 3/4 MOA.

Is this the normal barrel life span of a 6MM barrel? I don't have a clue about that, but is what this Hart 6MM barrel has done so far.......

Roland
Click to expand...

now we speak the same language! I love Hi-Walls and Low-Walls!! A 6mm Hi-Wall would be similar to sex in my book! I almost envy you!
gary
 
its all subjective. LOL there's a guy over on reloadersnest right now thinking a 6mm rem barrel is good for 50,000rnds!!!!!!!!!!! i suggested he was a tad optimistic.
 
Thanks for the replies.

I'm obviously not putting every conflicting point I listed out there as my position, just listing the various argument I've heard.

Whether it is due to shoulder angle, neck length or other cause(s) it would seem that the 6mm Rem doesnt usually have less barrel life than the others.
 
Some years back I asked Mike Walker about barrel wear as far as the .243 and .244 were concerned. He did not elaborate on the issue but did say that the .243 was considerably tougher on barrels than the .244. You can take that for what it's worth!
 
Cheechako said:
Gary

Can you cite specific evidence, other than anecdotal, that supports that statement?

Ray
Click to expand...

it's common knowledge that when using long bullets they often end up being seated way deep into the shoulder area. Yet with those very short bullets you end up with a lot of bullet jump. Now if you CAD out the case in a drawing accurately you will find that the TP is well into the barrel throat. Ackley points this out among others, and I have personally seen it myself. I do know of at least one guy that made his own .234AI off a 6mmAI reamer. I also know that he's been shooting that barrel for at least five years if not seven ( probably 350+ shots a year), and it still shoots in the fives ( coyote hunting rig). The gun he had prior to that was built by a well known person on this board (beautiful workmanship by the way), and it was in .243AI. The barrel started opening up at the 600 round mark, and by the 900 round mark was ready to replace. All he ever shot was 70 thru 80 grain bullets, and really not all that hotly loaded. He also ran into problems with fire forming and shrinkage, and ended up using 6mm Remington cases to make the .243AI case. That's why I use generic .243 cases to make my 6/250AI brass.
gary
 
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