308 Fire lap Question

Need a recommended start charge for a fire lap load

Been working on this all summer ...... I though it was me but Now i think it is this barrel

M1 Garand 308 barrel made by Citadel ( yes the cheep one- out of business )

its a new barrel less than 500 rounds of cast through it with some jacketed thrown in

I just bore scoped it and think it needs firelaping
I have seen worse and I have seen lots betterAttachment 302941

1 to smooth out the bore / rifling
2 to increase throat dia a tiny bit if it was 301, i could use any bullet

groups with it are not great cleaning it not bad (not leading with cast Water Droped)

any bullet with a nose over 301 will not chamber

311299 & the 30 xcb will not fit chamber with out pushing it back in the case or sticking a bullet

so have been using rcbs 165 sil or rcbs 150g fn .300 nose and that is border line tight

thanks

I'm a big 311299 fan and have used it in Springfield 03A3, and a M1A.
My mold is a old one from before they changed it from that Coke bottle shape to the new one that looks like a bore rider.

A little bit of chamber resistance is OK if you can chamber a round, pull it back out and see
Some engraving from the rifling on the nose. In a lot of cases, it will improve accuracy.
One of the Lyman books, I think it was the orange cover one that had a several page article about this.
That little bit of engraving on a Lead boolit's nose won't come anywhere close to causing a dangerous pressure spike.

You should still end up with the bolt being able to fully cycle, close, and lock from one round to the next.
If you're getting a push back into the case neck, ya might need a bit more (roll) crimp.


Everyone was all ga-ga about fire lapping back in the 80s-early 90s.
I'd go easy with it. People who got a little aggressive doing it trashed a lot of barrels.

I did a friends brand new Remington .308 that would not hit a pie plate at 100yards. Used jacketed ammo with "Flitz" impregnated into the jacket. Took 15 / 20 rounds but brought it around to a MOA shooter.

Do you know anyone with or are close to the tools to remove barrel? Being in the Garand receiver makes it kind of tough push through anything, pull through could be done maybe with muzzle guide but gets difficult at the end. What about if barrel removal is out go with making lead or epoxy lap set up avoiding the uncontrollable hard to monitor throat attack.
Maybe a couple hundred pulls with JB paste would get you where you are at least almost happy.

Not really sure about removing the barrel for what you have described. Hand lapping or fire lapping will work. Fire lap a couple and see how it goes. You can always finish up with some hand lapping. It really does do a good job of smoothing out a contrary barrel.

That barrel looks a lot better than my Savage and it shoots 1/2MOA with the right jacketed loads, close to 1MOA with cast. It also would not chamber 311299's without a lot of force. Like yours the RCBS 165SIL was a very good bullet. Now days I use a nose sizer from NOE to get the proper fit for the nose ride bullets. I like a slight resistance when chambering.

Also like yours the throat on mine makes the XCB seat deep into the case. The bullets still shoot very well, but, a crimp on gas check is a must.

If you feel you must lap it then be very careful. As mentioned above, many have ruined a decent barrel by fire lapping. If I were lapping I'd set it up for a hand lap instead.

I have seen to many barels ruined. The last one shot did it in> shoot and clenne with borteck ilimator. Will break in, in 50 too 100 rounds. Just use a plastic or aluninum jag. Bortec will desolive a brass one in no time>>

Well I started to fire lapp it
started with 5 rounds of the fine grit only
4.2 g of unique with a gc rcbs 150g fn .... I think i could see the bullet go down range App 4 ft of drop at 100

took it home and cleaned and bore scoped it ... maybe a very small change but it does look better

will try another 5 rounds of Fine next trip

Before you spend too much time with it I would suggest that you slug the barrel to make sure it's not loose at the muzzle compared to the chamber. I had a Savage that would shoot jacketed bullets at 1 1/2" @ 100 yds but cast was 4" plus. Slugged the barrel and it was .002" larger at the muzzle than at the chamber end. The slug would be tight at the chamber, begin to push easy about a third of the way down and fall out with gravity at about 2/3rds of the way down. Returned it to Savage twice and they never did fix the issue so I got tired of messing with it and sold the rifle. The second time I got a message saying it met their accuracy expectations but they never sent a target back with it.

Might save you some time and frustration if your barrel is similar. Hopefully that's not the case. There are several threads and stickies on barrel slugging on the forum if you've never done it.

Edit to add : While you're in there with your borescope, check to make sure your throat is concentric with the rifling all the way around. If the throat/leade is not concentric to the bore you'll likely never get a cast load to shoot with satisfactory accuracy.

Update
Well I started with 5 rounds of the fine grit only (Wheeler barrel lapping kit)
Hard to see any change 4.2 g of unique with a gc rcbs 150g fn .... I think i could see the bullet go down range App 4 ft of drop at 100
shot 5 over a chono ..... 850/ 900 fps

Next did 5 plus five rounds of Med grit =(10) and then cleaned and bore scoped a bit better also notices it had a bit of cleaning patch lint caught on a sharp edge at the gas port hole

next outing did 5 plus five rounds of course grit =(10)

So Have a total of 25 fire lapp rounds down the barrel and going to stop here, maybe a very small change but it does look better

I will repeat it here this 308 Barrel was not made very well, company that made barrel went out of business many years ago
it has some (still) ugly reamer marks that you can see with a bore scope

this rifle was to be my rainy day / take to the club / Hunt & shoot it and not worry rifle , Club level 100 yard fun shoot, etc
that i Do not care how many rounds go down the pipe, Cast just make it more affordable and 308 make it just a bit cheaper to shoot
parts were not the best looking and has no collector value, other than it a Garand, that I put together for my self.

I do have a another garand that I would not take out of the safe on a rainy day, that I like to shoot too that has a criterion barrel in it
that when you bore scope it looks way way better

Fine first, then medium, followed by course? sounds like the order is reversed to me.
With regard to the trajectory, it was my impression that any charge that got the bullet out the barrel was adequate.

Well, that 's a lot of fire lapping. have you shot it for score since the lapping? Any change?

Traditionally- metal removal is done with the coarse first, then medium, and the fine is done last as a polishing.

the Wheeler kit i have coarse grit is 220.

I am going to shoot it a bit and see what happens .. I can always use some fine grit in the future
Going to do a work up load using the 311299 . Was using the rcbs 165 sil as that was the only bullet that came close to fitting and extracting with out being pulled out of the case

Attachment 304798

This is a pic of the gas port , before barrel was put on

It shaved lead and snaged cleaning patches
it Does not do this now

I put some jacketed down barrel first the some cast/ then more cast then tried the lapping compound

Quote:

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Originally Posted by Winger Ed.

Everyone was all ga-ga about fire lapping back in the 80s-early 90s.
I'd go easy with it. People who got a little aggressive doing it trashed a lot of barrels.

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I've done a little of it and I'd advise the same thing; go easy with it.
Instead of the conventional abrasives, maybe try some JB Compound. It's less aggressive and non-embedding, so there's a reduced chance of ruining anything.

Nothing like upside down and backwards. Another customer in the works.

First thing about cast bullet shooting, bore, all of it, must be clean and smooth for the best results. Fire Lapping; Very, very slow velocity, just make it out the muzzle type slow, 5 shots then clean, examine. Course to finest in steps, no skipping steps. You must remove the crud with the course. Once all the crud is removed, and it is polished with the fine, slug the barrel again, start load development again. I have done literally hundreds of barrels.
Do you know what is used to finish fire lapping a 22 LR competition barrel? Pine rosin. That is a fine finish.
Good shooting.

Over the years I've fire lapped numerous rifle barrels. I've done 22LRs, 6.5s, 7mms, 30/31 cals and 8mms. Mostly milsurp barrels but a couple inexpensive commercial barrels also. Accuracy did, in fact, improve with all of them. No, it did not turn sow's ears into silk purses, but fire lapping did improve the accuracy.

Back in the early '90s I purchased a NECO kit and have been using it ever since. I believe Wheeler bought them out?

With 30 cals I've found the 311466 and the 311291 cast of linotype or WQ'd COWWs to be good bullets to use. I size the bullets .001 over groove diameter of the barrel. I most often just use NECO's "fall back" method which is 10 shots of each of the course, medium and fine grits and then 20 shots of the polish. I use Bullseye, Red Dot or 700X pushing either bullet to 1100 - 1200 fps. I initially use 10 fire formed cases (usually odds n ends cases) w/o any sizing. I do not further size the cases as no matter how well the cases are cleaned there will always be a grit or two to scratch the sizing die. I just deprime then reprime, charge with powder (I use a dipper) and hand seat the next bullet. The necks can be hand squeezed a bit to hold the bullet. After firing the cases are wiped off with a paper towel and reloaded with the next grit. I clean the barrel between grits.

Attachment 304999