How bad does pitting have to be before you would condemn a barrel? I have a couple milsurps that have light pitting in the bore. One is barely noticeable in the edge of the grooves (Finnish M91 VKT barrel). The other is only slightly worse and basically looks like really really fine sandpaper. I haven't shot either yet and am anxious to see what the accuracy will be like. FWIW both rifles have excellent crowns.
Light bore pitting in milsurps
- Thread starter davemccarthy707
- Start date
I've had some really poor bores shoot exceptionally well. The poop is however that a pitted bore will raise chamber pressure. A pitted chamber will be hard to extract. They usually go together. If there's little pitting don't worry about it. Sounds like that's what you've got.
Some visibly poor bores can still shoot well. The problem is when it is time to clean the bore after shooting. Some will never come clean with brush and patch. Otherwise, if it shoots fine, don't fix it.
For reference purposes here is what US Army Tech Order11W13-1-6 on rebuild standards for small arms says about barrels. "Fine pits are allowed if they do not affect the sharpness of the lands materially. Pits are allowed in the chamber if they are not large enough to cause extraction difficulties. Barrels will be replaced if lands are worn to the extent that accuracy is affected or if pits are as wide as the lands or grooves. Allowable length of pits for M1 Garand and M1 Carbine barrels is 3/8 in."
Bore evaluation for pitting or "frosting" as some like to call it, is a very subjective thing. Muzzle and throat erosion gauges are an objective measurement, but classification of pitting is another thing. As pointed out, pitting will strip and accumulate jacket material and make cleaning more difficult. As far as raising chamber pressures are concerned, there is a requirement for specified diameter gauges to pass the length of the bore, whether it is pitted or not. If they pass excessive pressure is not a concern.
Bore evaluation for pitting or "frosting" as some like to call it, is a very subjective thing. Muzzle and throat erosion gauges are an objective measurement, but classification of pitting is another thing. As pointed out, pitting will strip and accumulate jacket material and make cleaning more difficult. As far as raising chamber pressures are concerned, there is a requirement for specified diameter gauges to pass the length of the bore, whether it is pitted or not. If they pass excessive pressure is not a concern.
For reference purposes here is what US Army Tech Order11W13-1-6 on rebuild standards for small arms says about barrels. "Fine pits are allowed if they do not affect the sharpness of the lands materially. Pits are allowed in the chamber if they are not large enough to cause extraction difficulties. Barrels will be replaced if lands are worn to the extent that accuracy is affected or if pits are as wide as the lands or grooves. Allowable length of pits for M1 Garand and M1 Carbine barrels is 3/8 in."
Bore evaluation for pitting or "frosting" as some like to call it, is a very subjective thing. Muzzle and throat erosion gauges are an objective measurement, but classification of pitting is another thing. As pointed out, pitting will strip and accumulate jacket material and make cleaning more difficult. As far as raising chamber pressures are concerned, there is a requirement for specified diameter gauges to pass the length of the bore, whether it is pitted or not. If they pass excessive pressure is not a concern.
I guess mine are "as-new" then
- Location
- Tucson, Arizona
Best way, shoot it! If it is accurate, why worry?
A low mileage bore can show pitting because someone fired 1 round of ammo and neglected to clean it. It'll still shoot well - it'll just foul more easily. Dont bother to try to keep it squeaky clean as you're wasting time and cleaning materials.
For me it's not so much pitting what would be a reason to worry about accuracy.
Sharpness of rifling,extend of wear of it or bits of rifling rusted away is what's important to me.
I use casts WW boolits,not jacketed projectiles so it might be a different for someone else.
Sharpness of rifling,extend of wear of it or bits of rifling rusted away is what's important to me.
I use casts WW boolits,not jacketed projectiles so it might be a different for someone else.
I'm embarased by any pitting, I try to keep all my bores clean as a whistle, never mind 3/8's in length! I'm actually giving my sister a mosin nagant, just because it has some frosting. I went out and replaced it, because it seemed out of place with the rest of the gang.
I know I shouldn't care, it shoots great, but every time I clean it, it aggravates me!
I have some dark bores that shoot very well. Other dark bores simply need to be loaded up to the next one thou. for good shooting. I tend to look at the overall condition of the gun rather than just the bore, but the bore is a large contributing factor of how it will shoot.
I picked up an $80 Lithgow SMLE at Lebaron's years ago that sat in my cabinet for ages, as the dark pitted bore hardly inspired any confidence in the rifle. More recently, since I'd began reloading, I decided to take her to the range for a test shoot and was happily surprised. It shot decently enough out to the 200 yard target.
I probably wouldn't pay top dollar for a rifle with a really dark barrel unless it was some unusual collectable, but sometimes the dark bores really do impress.
Frank
I probably wouldn't pay top dollar for a rifle with a really dark barrel unless it was some unusual collectable, but sometimes the dark bores really do impress.
Frank
I'm embarased by any pitting, I try to keep all my bores clean as a whistle, never mind 3/8's in length! I'm actually giving my sister a mosin nagant, just because it has some frosting. I went out and replaced it, because it seemed out of place with the rest of the gang.
That's called OCD my friend
{if your happy and you know it tune}
Ifffff youave OCD and youknow it wash your hands: Ifff youave OCD and youknow it wash your hands
Ifffff youave OCD and youknow it wash your hands: Ifff youave OCD and youknow it wash your hands
+1 Accuracy out of a clean pitted bore can be decent but after as few as 5 rounds accuracy can go south in a hurry because the pits catch both copper and powder residue. But you won't know until you shoot it.
- Location
- South of your border
I had a Mosin from '43 that wasn't rearsenaled and its barrel was heavily pitted but it shot fine.
