BBL life with cast boolits?

[Shuz]

Assuming a person shoots cast boolit loads that are in the 1500 to 1900 fps range, how many rounds can be shot before the throat starts to erode or the rifling shows wear?

[green mountain boy]

gosh i would love to give you an answer...however many factors come into play. speed you are pushing,powders used,what is the BBL,shot hot?, etc. many here will have a much better answer than can i. all i know is i have shot my Remington 700 30/06 several thousand rds of cast in the 950-1700 fps range and it still shoots better than i can. my childrens children will be able to shoot it as well i am convinced.

[Winger Ed.]

There was a article in a older Lyman Cast book about that.
I want to say it was the one with the orange cover, but that may not be right.

They figured a common sporting rifle barrel will last approx. 2,000 rounds before there is some throat erosion, and accuracy begins to fall off.
They took a new Winchester (I think) in a .30 caliber, and fired it 40,000 times with cast.

Then they ground off the top of the chamber, measured it, and found 'no noticeable wear'.

[M-Tecs]

Barrels do not wear out for the most part. They erode out from heat from the gas and pressures . A standard 308 Match rifle with jacketed bullets will start having long range (600 plus yards) elevation issues around 3,500 rounds give or take. Normal hunting accuracy will be double or triple that.

A 45 ACP match pistol shooting cast should go well over 200K before you note internal barrel wear. Possibly a lot more.

Mostly it's dependent on heat and pressure.

22 Rimfire erode from the ground glass in the priming compound. You can see it with a borescope at the 6 o'clock position at 30K to 50K.

[Hick]

I've got 1960's 30-30 (post 64) that was well used when I bought it-- and I've run close to 20,000 rounds through it and seen no effects yet. If I seat a bullet to touch the lands the OAL is just what it used to be when I first bought the rifle.

[Whole Bunches]

I measure my bbls for throat wear if I have a gage that fits the bbl and action. With the exception of two 5.56 MG bbls, I shoot 5-8 shots (8 shots for the M1 and 5 for all else) and let the bbl cool to ambient temp with the aid of a bbl cooling fan.

This was 14 years ago. I worked up an accurate cast bullet load for my 3006 M1 rifle that functioned 100%. Don’t remember the exact load, but it was IMR4895 with Lyman 311291 with #2 alloy and sized .311”, probably in the the area of 35-40 gr 4895. I fired 800 rounds of the cast bullet load and compared the throat erosion to firing 800 rounds of 168-172gr jacketed match bullets with 46gr IMR 4895 in the same WWII M1. The throat erosion with cast was 1/3rd that of shooting the jacketed bullets. Less powder and bullets softer than jacketed was my thought. A longer test would be more accurate as the wear was very small to gage using my eyes and a gage that has 1/10th inch graduations.

FYI, no bore leading and no leading around the gas port and no leading on op rod. When the gas cylinder plug/screw was removed, there was a thin wall of lead that had formed against the inside end of the screw...easily knocked out. Otherwise, no leading inside the gas cylinder.

Shortly after, my house burnt and 99% of my casting items were lost. I started back into casting about a year ago.

[44Blam]

If you are shooting lubed, cast boolits in the 1500-1900 fps range you will likely pass that rifle on through your great grand kids.

Lead does not really erode a bore too much even when pushed a "little' fast.

Even barrels I've shot jacketed ammo out of don't really degrade.

As a contrast, I had an FN49 that was actually used in war in the middle east - the bore was pitted and scarred and just plain ugly. I could still hit a 2' target with the irons at 625 yards consistently with that thing.

With lead and non corrosive primers/powder you can shoot millions of rounds through a gun and still have a good gun.

Now, the hot-dog rounds like 6.5 creedmore and grendle - shooting those with copper jacket rounds above 3000 fps will very likely erode a bore. But at sub 2000 fps? naw.

[charlie b]

What is your criteria for wearing out?

Bench rest shooters would probably say when the barrel will not shoot less than 0.2" groups anymore. Most 'normal' people would not notice anything until they could not get 1" groups.

[mehavey]

If you are shooting lubed, cast boolits in the 1500-1900 fps range
you will likely pass that rifle on through your great grand kids.

What's the scoop (if any yet) on PC'd lead bullets ?
(Otherwise BP shooters, who've maintained/cleaned properly, "essentially" forever.

[Whole Bunches]

What is your criteria for wearing out?

Bench rest shooters would probably say when the barrel will not shoot less than 0.2" groups anymore. Most 'normal' people would not notice anything until they could not get 1" groups.

MY criteria for wearing out: I am not a bench rest shooter. I don't compete except in local military rifle matches shooting at 50 and 100yd targets. I do hunt, mainly hogs for hog control for multiple farmers. But my main shooting is simply plinking at cans and steel with the guys. I use the USGI criteria for small arms of 1" of throat erosion (rifling has worn away for 1" in front of the chamber) = new bbl time. I've worn out several M1919A4 MG 3006 bbls. When the gage showed 1" of wear (the reject line on the gage), within 250-500 more rounds the 100yd "group" would suddenly go from a few inches to feet wide. Those unlined bbls would consistently be worn out at 5000 rounds (fire a burst of no more than 20 rounds and let cool). USGI 5.56 and 30 caliber gages all used the 1" worn criteria. Note: Been retired from the military since 1988...I do not know what the current criteria and manuals now say. A M16 bbl when at the gage reject line would also now be inaccurate with sometimes keyholed hits.

And, FWIW, I have a "collection" of various 300 Blackout bbls of different steels and/or bore treatments I've been shooting for years as a hobby/personal project with a total Blackout round count in the 20,000 range now. Going from shortest life to longest: Plain 4140 button rifled, plain 4140 CHF, plain 4150 or 41V50, 4150 CHF, 4140 nitrided, 4150 nitrided, 4140 chrome lined, 4150 chrome lined, 4150 CHF chrome lined, 4150 CFH double chrome lined. Based upon throat erosion so far, in the Blackout, plain 4140 will go about 11,000 jacketed rounds until the TE = 1" wear. 4150 or 41V50 CHF double chrome lined will go about 23,000 rounds. This is all 5 shots and let cool. In other words, anything added to a bbl beyond plain button rifled 4140 steel adds to its life in regards to throat erosion (TE). Life calculations are done with rounds fired so far vs TE so far, extrapolated out to 1" wear...as more rounds are fired, the calculations will get more accurate.

I don't care what people post, in my experience, using TE gages, at least with the Blackout, nitriding (or whatever you want to call it) does not last as long as chrome. CHF in and of itself adds about 500 rounds to a plain bbl. Firing .310" or .311" jacketed bullets does not wear the bore any faster than using .308" in the Blackout (I shoot a bit of pulled 124gr 7.62x39 FMJ bullets in some of the Blackouts for plinking/practice). In the .223/5.56 I don't have as much measurement data, other than to say plain 4140 wears faster than nitrided, and nitrided, so far, is wearing faster than chrome lined, but not by much. I do have 2 4140 button rifled chrome lined M16 bbls shot full auto (20-30 rounds and let cool) that are only used for full auto...holding up fine with that level of shooting, but only a couple of thousand rounds through each so far. 1 11.5" and 1 20" from Model One Sales. Without looking up my records, I'm pretty sure they've shown no TE wear so far.

Others certainly can have their own bbl wear criteria. So far, none of my Blackouts have turned inaccurate. As far as which is more accurate, there's no telling for me. A Daniel Defense Blackout bbl is the most accurate I have. It was so accurate that I bought another...it turn out to only be "average" accurate. I have 2 Ruger American Ranch Rifles in Blackout. Both are nicely accurate and like the same loads, but one shoots consistently slower than the other. Another maker (Delta Company) of a plain 4140 bbl said if I ever wear it out, he'll replace it for free...he went out of business, oh well. A Ruger engineer said if I wear out a RARR Blackout bbl (plain 4140 CHF) they will replace it for free if they an have the old bbl, my firing records, and can cut the bbl in half lengthwise to examine, and will give me the other bbl half. Most companies were very upfront with what steel and making methods they employed. SIG wouldn't tell me at all, saying it's propriety info, but I got some bbl info from reports and SIG advertisements. It's a fun journey, and I like keeping records that add to my enjoyment.

[Shuz]

What is your criteria for wearing out?

Bench rest shooters would probably say when the barrel will not shoot less than 0.2" groups anymore. Most 'normal' people would not notice anything until they could not get 1" groups.

Charlie--My criteria is not being able to shoot sub MOA groups at 100 yards in CBA matches. OK folks, here's the whole story:
I have a Savage Mdl 16 "Weather Warrior" stainless steel in .250 Savage. I worked up a load of 14.3g of Reloder 7 behind a 100g Saeco 100 boolit. It always shot "around" 1" at 100 yards, sometimes a little more, sometimes a little less. Well, last Saturday the 4/ea five shot groups that I fired measured 1.507,1.375,1.583 and 1.680. Needless to say, I was disappointed based on the way this gun used to shoot for me. I've had this rifle for about 10 years and I figure it has 3 to 4 thousand rounds of only cast boolits thru it. Based on the answers already received on this issue, I'm beginning to think that the problem lies with the shooter, not the gun. Last Saturday I had many times where the Savage Accu-Trigger kinda released, but the safety kept the gun from firing. This happens if the blade in the middle of the trigger is not compressed completely before the rest of the trigger is squeezed. When this happens 3 or 4 times and you have to open and close the bolt each time, it tends to break ones concentration. I think this is happening because I have developed periferal neuoropathy and I've lost the feeling in my fingers and therefore I am applying pressure to the side of the trigger instead of making sure the blade is depressed completely. Anybody else have this problem? Any suggestions to help me?

[AndyC]

Fascinating data, Bunches - thanks for sharing!

[DonHowe]

The thing to worry about ain't bullet material unless you are shooting steel jacket maybe. The culprit is the heat generated by full factory level pressure/velocity loads. That varies to some extent according to powder used. There are other factors, one of which is cartridge design. As has been stated before, how a rifle is used and what is expected of it in terms of accuracy help determine how much barrel life vs accuracy potential matter to the rifle owner. If that matters and you shoot full pressure jacketed ammo buy a .308. If it doesn't buy a 6.5 Creedmoor.

People who buy a six five Creed (that is as hard for me to type as to say) based on advertising hype and the BIL's testimonial and actually shoot it a lot AND EXPECT ACCURACY (as hyped) are in for a surprise in terms of barrel life. In shooting disciplines rounds like Creedmoor and the 6mm PPC were designed for users KNOW they will have to replace barrels due to throat erosion. The same is true for .308 but barrel life is much longer.

[waksupi]

Assuming a person shoots cast boolit loads that are in the 1500 to 1900 fps range, how many rounds can be shot before the throat starts to erode or the rifling shows wear?

I think it was Felix that stated a barrel with some throat erosion will shoot cast better than a pristine barrel.

[charlie b]

Shuz, Good info.

I can only say I also have those good and bad days. I also have a Savage for shooting cast, 12BVSS in 308 (it has just over 3000 rounds through it, about 2000 of those cast loads).

It might be the trigger. Mine will sometimes 'trip' for what seems like no reason at all. It is the varmint trigger and set to minimum. It will 'trip' if I move the rifle too much (like lifting if off the rest and then reposition). I know that kinda screws up my tempo as well. It usually happens when I am in a great position, rested, relaxed, shooting well and then.....nothing. If the trigger continues to act up then try increasing the pull weight just a little and see if the problem continues. If so, then it might be from not pulling straight. Dry firing would help pinpoint this.

Barrel erosion could be a key if you consistently see larger groups than what you used to shoot. I would definitely keep track of group sizes just to be sure. But, cast are kinda different as waksupi said.

[Bang Switch]

There's a good possibility that you won't life long enough to wear out a rifle barrel shooting lead bullets.

[country gent]

Another factor that directly affects barrel life is rate of fire. Those blasters who go thru 300-400 rds a day at high rates of fire barrels will go much faster than the slow methodical shooter. High power shooter see this when they shoot the infantry trophy match ( rattle battle ) roughly 120 rds thru the gun in 45 mins. The barre; on a garand or M1A ill be so hot it will raise blisters. This is also hard on bedding and the rifle itself not just the barrel.

Over bore cartridges ( large powder capacity small bore) ate harder on the barrel than milder cartridges. the 30 cl mags are harder on throats than the 30-06 which is still harder than the 308. the mild 762 x 39 is one of the easiest 30 cals.

Case design also plays a big part a shoulder angle neck length that keeps the first "hit" of powder gases in the neck has a venturi effect lowering the effect. The 6 ppc showed this when it was introduced. I had a good friend that shot a 6 mm 284 in 1000yd matches and he claimed 1300-1500 to a barrel

The lowered powder charges, methodical pace, and lowered heat all extend the life with cast bullets. Very few cast bullet shooters run the high rates of fire in rifles

[Nobade]

Reading the Harry Pope book, he said after 125,000 rounds his barrel had .0001" of wear. Those old 32-40s were pretty easy on barrels!
As for the creedmoors, I typically see customers wanting to replace barrels at about 4,000 rounds with the 6.5. At that point a good shooter is losing matches because of his rifle. In the 6mm version, they are toast at 900 rounds. That lighter recoil comes at a price!

[M-Tecs]

The 6MM Creedmoor is basically the same 6mm XC, 240 National Match, 6mm Internal and a whole host of other 22-250 based cartridges. Most of them are lasting 2,500 to 4,000 rounds competitive barrel life before that start losing points to elevation at the 600 to 1,000 yard range.

The 6mm XC is a ballistic twin to the 6mm Creedmoor. My personal ones plus the ones I have barrel have all made it over 3,000 rounds competitive life and in the case of my personal guns they are still going strong as prairie dog rifles.

The 6mm Competition Match is a 243 based cartridge with a steeper shoulder angle and increase case capacity. Using slower powders and abrasive cleaner the designer Joe Hendricks is claiming normally over 4,000 rounds competitive life. He won the National one year with a barrel with over 2,500 rounds on it.

https://www.longriflesinc.com/produc...nt=11004783681

https://www.longriflesinc.com/blogs/...petition-match

https://www.longrangehunting.com/thr...-by-mcr.95524/

https://forum.accurateshooter.com/th...tions.3947022/

Those barrels will still have a significant barrel life left for under 500 yard applications like prairie dog shooting and an even longer life as a deer rifle.

[Bad Ass Wallace]

I have rifles that shoot 'J' boolits and 'special' rifles that only shoot cast boolits. I shoot a lot (6-7000 rounds per year) and in 50 years I have never shot out a barrel with cast boolits! I do delight in showing off the pristine mirror bores of my Cast boolit shooters.