Normal throat erosion?

J

jaybic

Guest
Hey guys,

I have a 22-250 and shoot a 50gr vmax thru it fairly close to maxed out with H4895. When it was brand new on 08Sep06 and had never been shot, it measured 2.080 to touch the rifling using a stoney point measuring tool and comparetor(sp?) and a Lyman dial caliper.

Today, it measures 2.115 to touch the rifling with the exact same bullet I used then for the dummy round. Has the throat of my rifle eroded that much and is that about normal for maybe 1500-2000 rounds? I this enough erosion to start seeing signs of eratic accuracy?

I dont know if thats alot or a little erosion.

Thanks all,

Jamie
 
the proof is in how its shoots. does it still shoot well? if not, have you adjusted your seating depth any?
 
You know I've been wondering the same thing. How many shots can a good barrel take before accuracy begins to permanently and significantly degrade?
 
I have never seen a .22-.250 barrel with 500 rounds down the pipe that had a throat left. That is the vary top for the sweet spot in this chambering for top barrel life. After 500 it's "I hope I have the room for cut off and rechamber".
 
Huh?

Big Al said:
I have never seen a .22-.250 barrel with 500 rounds down the pipe that had a throat left. That is the vary top for the sweet spot in this chambering for top barrel life. After 500 it's "I hope I have the room for cut off and rechamber".
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My factory Rem 700 has 2000+ rounds down the tube and still can shoot 2 1/2" @600 yards, I have done it repeatedly and recently, in a match. Now I don't shoot maximum pressure and I do expect for accuracy to suffer some day, maybe some day soon. But I think to say that at 500 rounds it's time to re chamber may be premature. Unless your being funny and pulling his leg, in that case I agree with you completely, 500 rounds is beyond maximum.:D
 
my factory savage lrpv 22-250 using rcbs precision mic set is showing a .010 diff. from new i have been seating .025 off lands and i have adjusted seating depth according to barrel erosion and i have only fired about 250 rds through it but in working up my loads i fired several hot loads in it which may have caused this but rifle is still shooting in.2s at 300yds . this gun was very funny and hard to find a good load for but after many different loads i found h414 40gr mag primer 52gr bergers seated .15 off lands to be a good choice
 
My 22-250 AI has severe throat erosion

My gun smith that chambered my rifle says its pretty bad. But it still shoots great 1/2 MOA sporter weight 26" 8" twist SS 5R BBL. This is my predator rifle.
 
rrendina said:
My factory Rem 700 has 2000+ rounds down the tube and still can shoot 2 1/2" @600 yards, I have done it repeatedly and recently, in a match. Now I don't shoot maximum pressure and I do expect for accuracy to suffer some day, maybe some day soon. But I think to say that at 500 rounds it's time to re chamber may be premature. Unless your being funny and pulling his leg, in that case I agree with you completely, 500 rounds is beyond maximum.:D
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I'm not being funny at all. If you have a barrel that will only shot if the bullet is seated in the lands and you keep chasing that point, as the throat
wears and you chase the lands, you are going to run out of neck length before you hit 500 rounds. Or if you shoot at .010 off you are going to run out. So then, this being the case, what do you do, shorten up and deepen the chamber? NOT with my reamers you don't. You cut the chamber off until you get back to undamaged barrel and cut a new chamber. That is what this ctg makes us do.

By the way if my barrels shoot there best with what ever seating depth that works best for that barrel, then that's where I seat at. By the same token, what is acceptable accuracy for you, may or may not be the same for me.

It's the same with barrel crowns, how many shots do you have before you need to recrown? The answer is when the barrel needs it, there is no way in hell you can tell, without checking @ 10X when you need to recrown.
 
Al, I'm not disagreeing with everything you said, just the every 22-250 you have seen need to be re chambered after 500 rounds. I do agree that some one can wreck a barrel in 500 rounds. My 22-250 has evolved to the point that the bullet will only seat half way in the neck of the case, last time I checked that was .012" off the rifling, who knows how far it is now .It still shoots well so I cant see the point in checking throat erosion any more, I just cant chase it. When the accuracy goes away it will be new barrel time, something I am, in a way looking forward to.
 
I don't think you can put a definite number to it. I've worn out chromoly factory barrels fairly quick and have stainless barrels by different manufacturers that have lasted either about the same or much longer. Pretty much depends on the barrel and the load and shooting habits. Get carried away and don't pay attention to heat, you could probably fry a barrel in one afternoon. If it's a factory barrel, .035" wear sounds realistic for 1500 - 2000rds in that chambering. As the throat gets longer, just follow it with seating depth. Only you can tell what's happening with accuracy.
 
As long as you can use your OAL guage and comparator to continue loading a couple hundredths off the lands, I don't see why the gun should not shoot okay. In other words, as more shooting is done, you would increase OAL to maintain closeness of the ogive to the lands.

When a throat is really shot out, you have so much throat gone you probably couldn't even find the lands with an OAL guage.

As for wearing the throat and barrel, there are a number of factors, including shooting a very hot barrel.

I am not sure that hot loads would be a major reason for ruining a barrel. It could possibly be one factor. Barrel steel is designed to endure very high temperatures.

With competition benchrest rifles, they are probably off their peak and beginning to lose it with far fewer rounds through them is the case than the varminter or hunting rifle. Because to be competitive, these rifles have to be unbelievably fine tuned.

I shoot about 500 rds per summer through my 22-250. Does this mean I need to rebarrel every summer? Sorry, I just can't afford it.

Has anyone posed a question like this to the big arms companies, such as Savage or Remington?

I see these guys at the shooting range with the black "tactical" rifles firing "pop" "pop" "pop" "pop." They can go through 75 rds in about ten minutes. Those barrels must be hot enough to fry eggs. Lord only knows what this overheating is doing to the bore.
 
The sweet spot for the .22-.250 is about 500 rounds! I stand by what I wrote. That does not mean that the barrel does not still deliver the kind of accuracy that you want. With that barrels throat, the best that barrel is going to give is gone. Unless it's re chambered. All of our hot rod .22 center fires are in the same boat. I don't care which one you point to, they all have a shorter life above 3700 fps than the ones shooting at 3200 fps. The problem gets into that big dog town you get into. Better have water with you, that barrel is going to cook unless you can get the heat out of it.

Does that mean I don't shoot them because they burn out fast? Heck no, I love the darn things and will not give up on them. Just remember the faster the bullet goes, the faster the barrel goes, this is the price we pay for the fun we have.

Next time you go to a gun show, check out the hot rod .22 CF's, vary few have barrels I would pay money for. A good example is the pre 64 M-70's in .220 Swift. I've never seen one that was not gone in the throat. Remember these low recoil rifles are fun guns. I saw one once that the only rifling left was in the last several inches from the muzzle. I remember asking the guy that had it on his table if he used it with shot loads?
 
My 22-250 came into it's own around 700 rounds and has been shooting better and more consistently since. Like I said earlier, it's just a matter of time before I re barrel.

With sublime certainty, one could ruin a barrel less than an hour. On the same note, one could load, shoot, and clean a barrel in a manor that would extend its life and accuracy considerably.
 
I seen a M700 factory rifle in 22-250 at a gun-show a while back that only had rifling in the last few inches near the muzzle, the bore was smooth and shiny though ! :eek:
 
22-250 AI shooting 80gr

Big Al said:
The sweet spot for the .22-.250 is about 500 rounds! I stand by what I wrote. That does not mean that the barrel does not still deliver the kind of accuracy that you want. With that barrels throat, the best that barrel is going to give is gone. Unless it's re chambered. All of our hot rod .22 center fires are in the same boat. I don't care which one you point to, they all have a shorter life above 3700 fps than the ones shooting at 3200 fps. The problem gets into that big dog town you get into. Better have water with you, that barrel is going to cook unless you can get the heat out of it.

Does that mean I don't shoot them because they burn out fast? Heck no, I love the darn things and will not give up on them. Just remember the faster the bullet goes, the faster the barrel goes, this is the price we pay for the fun we have.

Next time you go to a gun show, check out the hot rod .22 CF's, vary few have barrels I would pay money for. A good example is the pre 64 M-70's in .220 Swift. I've never seen one that was not gone in the throat. Remember these low recoil rifles are fun guns. I saw one once that the only rifling left was in the last several inches from the muzzle. I remember asking the guy that had it on his table if he used it with shot loads?
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3,700 FPS . Isn't it the powder and primer combonation that burns the BBLs.My Rock creek 5R 8" twist bbl have throat erosion but is still shooting well. I mostly shoot 80gr Bergers.
 
It is an old bit of wisdom that rifles losing their throat can still hang onto accuracy if the reloader goes over to long bearing surface bullets.

I had a 30-06 that was getting shot out. I went to the 200 grain Sierra Matchkings and retained good groups. Lighter bullets like 150 gr would surely do very poorly in this bore.

This is a well bit of shooter's wisdom that has been around since the 1930's.
 
Years ago Jim Carmichael (OUTDOOR LIFE)wrote about a 220 Swift that had 4000-5000 rounds through it and still shot groups suitable for varmint hunting.

Some bores with rifling that looks badly eroded still shoot pretty well for hunting. Some bores that are badly pitted still shoot pretty well. You can't predict accuracy by looking at the rifling and there is no "rule of thumb" about how many rounds a barrel of a given cartridge will last. Just keep shooting it until it quits.

On the other hand, I wouldn't buy a hot rod 22 caliber with a badly eroded throat expecting to get another 1000 rounds out of it. Sometimes they quit shooting all at once.
 
Reminds me of the old military 30-06 Springfields. Most had 4-groove barrels, but some had two-groove barrels.

One guy named Peterson was out at a club match, and told us he was using a two-groove barrel. We all laughed, and thought it was a joke.

It shot about as well as the 4-groove. We stopped laughing.

You have to try each gun.

If groups seem to be falling out, changes in your reloading recipes might bring them back. Esp my point above about "longer bearing surface" bullets.

Worth a try anyway.

None of us can afford to rebarrel every 500 rds or we would go broke.

This does not apply to the heavy bench rifles, which use a different logic.
 
22-250 barrel life

An original Remington 700BDL Varmint contour began keyholing, at 100 yds., and just before that copper fouling became a problem. This all occured at 2350 documented rds. That barrel was replaced with a Stainless Hart, and heavy copper fouling began at approx. 2000 rds., keyholing at a documented 2435 ( I keep a log book for each of my rifles), and that barrel was replaced, this time with a 22BR chambering. So, from my personal experiences, the "life" of my 22-250 barrels was in the area of 2200 to 2400 rds. The vast majority of loads were the "standard" 38 grs. of H380 with 50 to 55 gr. bullet weights, and all firing was "slow" single-shot, never letting the barrels get hot.
 
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