Author Topic: ? on Barrel erosion (Read 946 times)

bryan · « **on:** December 15, 2003, 04:38:24 PM »

How many rounds does it take before the barrel starts erode? I have read several articles and they haven't helped much. I am thinking of getting a new WSSM or WSM cartridge gun but I don't want something that won't last. I would be using it for varmint and big game. Thanks for any help you can give me.

Iowegan · « **Reply #1 on:** December 15, 2003, 05:59:03 PM »

Bryan, That's not an easy question to answer because so many things can directly contribute to erosion. Most erosion takes place in the throat of the barrel, not the bore. It can be caused by hot loads, rate of fire, improper cleaning, and a host of other things. Case design is probably the single biggest problem. Cartridges such as the 264 Win Mag have an average barrel life of 500 rounds. Military cartridges such as a 223 Rem, 308 Win, 7mm Mauser and 30-06 can easily exceed 100,000 rounds barrel life.

Generally, the more radical the case body to bore diameter, the shorter the barrel life. Also, the higher the operating pressure, the shorter the barrel life. There are exceptions. Maybe another member has more info on the WSM's but I would think they would have short barrel life due to the high operating pressures and radical case to bore diameter.

There are some things a shooter can do to reduce erosion. Keep the chamber / bore clean and free of rust and fouling. Space your shots so your barrel doesn't get too hot. Use ammo that is not loaded too hot. Select a barrel made of chrome molly alloy. Select a cartridge known for long barrel life.

gunnut69 · « **Reply #2 on:** December 15, 2003, 06:21:14 PM »

I agree with most of what iowegan said. Probably the most imortant factors to control are rate of fire. Control the heat in the barrel steel to minimize the effect each shot has on the throat. Load to lower pressures. The rounds that erode the worst have the highest case to bore ratios, and are all high performance rounds. A 22 Hornet will deliver a 40 grain slug at nearly 3000 fps. The 220 swift a 45 at close to 4000. The swift makes that velocity gain by burning 4-5 times the powder charge thru the same bore. Still it will produce good accuracy for several thousand rounds if properly maintained. The Hornet will last nearly forever.. Still if you want the performance you will have to pay the price.. The short mags are contain large powder charges and generate high chamber pressures. The 243 WSSM was recently reviewed in a gunmag. The case walls were demonstrated via a sectioned case. They were probably twice the normal thinkness. The velocities generated by factory ammo could not be reached. My guess is the favtory loads will moderate when enough rifles are sold. The loads simply generate more pressure than the companies would normally use, in the interest of selling a few new rifle. When sales sag, the loads will be reduced to more moderate pressures in the interests of safety.. Buy what you wish, and wear it out if you can. Then rebuild... It's all part of the game!!!! Don't expect any great gains over the standard mags just because of the new shape..not in the cards. All the articles seem to be saying. There is a direct link between the velocity generated and the powder capacity in the case. Shape and length, not withstanding.

KN · « **Reply #3 on:** December 15, 2003, 06:46:58 PM »

Thats easy! ONE. How many rounds does it take before performance suffers? Thats not so easy. Depends on calliber, powder, charge, barrel quality, and probably 100 other variables. I wouldn't worry too much about it. From every thing I have ever heard or read it takes several thousand rounds to really start to notice a problem. KN

thecowboyace · « **Reply #4 on:** December 16, 2003, 09:51:01 AM »

gunnut69 & iowagen are on the money. I will say that a given bore that is never heated to an abnormal temperature, normal for a hunting rifle is not the normal for a rifle used in combat. Taking each into cosideration, gunnneut69 says, load to the lower pressures, each barrel will have xxx,xxx of barrel life in it when loaded with xyz powder and then only zz,zzz when powder abc is used in it. Take a NEF .223, which is capable up to 3700fps with the 40gr. Blitzking but loading it down to 3200fps which is certainly respectable, I do not believe that your father, you, your son, a
possibly your grandson will not wear the rifle out when shot as such. People talk about ordering 1000rds at a time, if you don't have a semi-auto, it takes a while to, when load a magazine up with 5 rounds, shoot that much ammo up. Loads at the 3200fps would certainly go 100,000 rds before really being able to notice that it is the barrel and not you, missing the target.

I have always meant to keep track of the rounds that I have put thru each rifle and pistol that I own but I don't. Not many do, I don't think. It would be nice to have thought about after purchasing a new, or even used, firearm to put it into a vise, padded most definitely, reloading your ammunition and shot on a truly average day, little to no wind, no brewing, temp 75' and shot say 5-5 shot groups and then do that every year that you own that rifle. Of course it will be off a tad just because of the powder being of a different lot. Anyone ever do that or close to this?

From what my gunsmith tells me, more barrels are used up by cleaning them to much, too hard, or in the wrong way. He has told me, if you buy a new firearm, break it in somewhat gently, and then make no more than 5 strokes with a bronze brush, then cleaned with swatches and use a bore mop and coat the bore with oil. Before you go shoot, run a couple of patches down the barrel to clean the older oil up, run a patch with a tad bit of oil on it down the bore. Also never bring back a patch that has been run down the barrel, just pull it off, pull the, preferably, single rod back out. Alway use a crown protector to preserve the muzzle and crown.

helobill · « **Reply #5 on:** December 16, 2003, 02:33:27 PM »

About the only thing I can add is to disagree slightly with Iowegan on the 264 mag. I owned one of those handed down from my father (wish I hadn't sold it now, but that's another story) and it took well over 500 rounds with no loss of accuracy. It did get a bad rap for short barrel life for a couple reasons, but as Chuck Hawk says, "Another complaint is relatively short barrel life. However, the .264 Mag. is no worse in this regard than any other cartridge operating at similar pressure and velocity." And the 264 Mag illustrates gunnut69's point, the original factory ammo pushed a 140 grain bullet to 3200fps, now both the Rem and Win factory load push the 140 grain to 3030fps.
Bill

bryan · « **Reply #6 on:** December 16, 2003, 06:14:04 PM »

Thanks for all the info on my question! All your input was what I was looking for. I am trying to do a little more homework than I usally do when I buy something, so I don't screw myself in the long run. I would like to be able to hand my rifles down to my kids when I can't shot anymore, hopefully many years from now!
Now that deer season is almost over, I will start checking the pawn shops for some bargins.
Gunnut69, Can you rebuild a barrel that has been eroded?
Thanks again

Iowegan · « **Reply #7 on:** December 16, 2003, 06:50:17 PM »

Back in the late 60's, I bought my first high performance rifle, a Sako Finbar chambered in 264 Win Mag. I used only factory ammo in it. The Sako would shoot sub-MOA groups and was perfect for long range coyote hunting. After several years and approx 600 rounds, my groups spread to 2". A hundered rounds later, it wouldn't hit a dinner plate @ 100 yds. I took it in to a gun shop where they made a chamber casting. The throat was eroded from .300 to .380 and looked like a pitted funnel. Needless to say, a new barrel was in order. Wish I had a chronograph back then. I'm sure the velocity dropped off quite a bit. I knew nothing of erosion so this was a good lesson. I'm sure if I would have handloaded and kept the velocity down I'd still be shooting that Sako. But then, what's the fun in having a high performance gun and shooting light loads?

I still have my old Rem 700 in 223 Rem that has had 10's of thousands of rounds run through it. It will still hold a sub-MOA group at full velocity. It's been used and abused. It's nothing to go out prairie doggin' and put 200 - 300 rounds a day through it. I'm sure it will outlast me and probably my sucessor.

helobill · « **Reply #8 on:** December 17, 2003, 07:43:38 AM »

Bryan,
You can't repair an eroded barrel, but you can replace it. (okay maybe not the average guy, but a gunsmith can)

Bill

bryan · « **Reply #9 on:** December 17, 2003, 12:15:57 PM »

thanks Bill!

Larry Gibson · « **Reply #10 on:** December 17, 2003, 02:02:46 PM »

"Take a NEF .223, which is capable up to 3700fps with the 40gr. Blitzking but loading it down to 3200fps which is certainly respectable,...... I do not believe that your father, you, your son, a possibly your grandson will not wear the rifle out when shot as such. ........ Loads at the 3200fps would certainly go 100,000 rds before really being able to notice that it is the barrel and not you, missing the target."

A hundred thousand rounds is a bit of a stretch. I have "shot out" several barrels over the years. I have kept track of the actual number of rounds fired in several rifles. However, a lot depends on what is meant by "shot out" or when throat erosian "effects" accuracy. The most rounds I have seen documented through a rifle were through an M1A used for IPSC matches. It was a SA Match rifle and would shoot 1.5 MOA with white box M118. The owner shot nothing but M118 and Special Ball through it with probably half of it being rapid fire. At just over 20,000 rounds he had it rebarreled and rebedded as a TE guage was maxed out and groups were 6+ MOA. Keep in mind that 6+ MOA is still acceptable as "serviceable" to some.

Several barrels I shot out were in .308 Winchester as match barrels on M14/M1A match rifles. They were used with a combination of slow fire and rapid fire during service rifle competition during the National Match Course of fire. They lost their "match accuracy" (2 MOA max) at around 8,000 rounds. I had one M1A barrel with 12,000+ rounds before it went over 3MOA and ran a 9 on a throat errosian guage. I have a couple barrels on match bolt guns that show little erosion after 6, 000+ rounds of truely slow fire, both are less than 2 on the TE guage. However once throat erosion really gets started it goes fast.

I have a Rem M700V I got in '72. It is a .223 with 1-12 twist. It would shoot in the .5s and .6s with a 55 SX at 3200 fps when new and through around 7,500 rounds. I used it shooting slow fire on varmints. After 8,500 rounds the SX bullet would not touch the lands when barely seated in the neck and it wouldn't hold MOA, that's how fast it went. I had to take 1.5" of the breach end when I set the barrel back to get good rifling in the throat again. It went back to shooting in the .4s and .5s. I've put another 1,200 rounds through it and its probably good for another thousand or so rounds.

A 6.5-280 was good for 1500 rounds before I had to set the barrel back. Lots of old 4831 sent down that bore. A couple .22-250s rechambered to 22-284 were good for only about 500 rounds each. My hunting 30-06 has a little over 3,000 round of 180 gr bullets pushed by a case full of 4350 and I can feel the roughness in the throat with a tight patch. I don't expect it to last much longer shooting MOA.

Most rifles or other guns are worn out through abuse but a few do get "shot out".

Larry Gibson.

bryan · « **Reply #11 on:** December 17, 2003, 06:46:15 PM »

I think I have located a Rem 270 at one of our many pawn shops today. I didn't get a chance to inspect it. From outward appearence it looked almost new, I think it was 375.00. With deer season closeing soon I am sure they will come down some. I have looked at alot of new rifles the last few days and I just don't like the stocks they are putting on them, I think they look real cheap, but the ones that look good cost several hundred more. I am a big Ruger fan so I have on more place to look for a M77 and maybe I can talk myself into buying it.
It would take me forever to put 1000's of rounds down range, but I can try!
All this info has been a great help to me. Thank you !!

Iowegan · « **Reply #12 on:** December 18, 2003, 06:26:13 AM »

I'm confused! Is the gun a Remington or Ruger? There is a 270 Winchester, a 270 Weatherby, and a 270 WSM but no 270 Rem. There is a 260 Rem and a 280 Rem.

Know what you mean about the stocks. It's getting hard to find a rifle with decent wood without spending a premium. I like the looks of a wood stock but for beating around in the brush, the composite stocks are much better. They don't swell or shrink with humidity or temperature and if you get a ding or scratch, some flat black spray paint takes care of it. The last two rifles I bought both have black composite stocks and I must say, despite being ugly, they are more functional.

bryan · « **Reply #13 on:** December 18, 2003, 10:18:18 AM »

Now that I think of it it my be a 270 Win. Like I said I didn't inspect it or even handle it, just looked at it on the shelf. But compared to the rest of the guns they had, it looked almost new.