Home Forums Hunting & Shooting Gunsmithing Rough spot in bore - Model 70 Safari Express

I bought a like-new Safari Express in 375 H&H from a fellow here on the Fire. It had been shot very little, and that fact was obvious. After a day at the range however, I noticed a LOT of copper fouling in the last 1.5-2.0" of rifling from the muzzle back (think solid orange). When running a patch through the bore, I can feel that it's rougher there, and I can even see light chatter marks on one of the lands. Clearly, there was an issue during rifling.

The thing is, the gun appears to want to shoot. Having grabbed a bunch of my Barnes TSX handloads from my other .375, it put most of them into 1-1.5" at 100 yards, and that load was for another gun. What's more, I had removed and reinstalled the scope between shots here. I don't know whether to continue with load development, or send it to Winchester and have them fix it.

I do have JB bore paste, but that's not going to remove the machining marks. If it shoots well, will these imperfections smooth out over time? I'm reluctant to fire lap or hand lap the bore if it's shooting well, but it bugs the crap out of me...

Yes, the machine marks will reduce as you shoot it. If the rifle shoots decent groups, ignore the rough spot and enjoy the rifle. You could try loading some of the abrasive bullets sold by David Tubb. Might help, might not.

RAN

If it really bugs you, look into making lead lapping slugs and using fine valve compound. Clearly, you have a gun with potential, which you COULD mess up.
I've gone absolutely nuts on barrels that shoot poorly, and gotten about 2/3rds of them to improve a lot (the others are now scrap) but barrels that shoot well are tinkered with a little at a time.
Safest way to go is to go after it with the copper remover, get that all gone, then try to polish it with JB. Call it an extended break-in.
The marks are on the lands, so that will go away first.
But if it shoots with a workup -- like under an inch -- then maybe you'll be fine just shooting it and staying after the copper until the fouling relaxes.

By the group picture. If it isn't broke don't fix it. Shoot it and clean it.

You might also think about having the barrel shortened a couple of inches and recrowned. There's a lot of barrel on a safari express & losing a couple of inches wouldn't hurt anything.

I've gotten barrels to clean up using lapping by fire lapping. Fire lapping converted a 300 Win Mag from a 1.7" to about .6" with the right loads. Similarly I got a 280 Remington to decrease group size greatly. This last deer season I took the 280 out with 154 grain and 162 grain Hornadys. The 154's shot ~ .5 inch and the 162's shot ~.7"

Hand lapping may do better, but for a 'wanna be' gunsmith the fire lapping worked well.

Anytime a high power rifle shoots hunting load groups like those, I am very pleased.

If it turns out to be a problem, this is a great idea. I could lop it off to 22" and lose virtually nothing. I'm going to shoot it for a while, work on the rough spot with JB, and then resort to this if necessary. Thanks.

Shoot some Speer 235 or Hornady 225 bullets thorough it and clean when you see any fouling.

I would just shoot it. I doubt a spot near the muzzle will ever wear down enough to not grab copper, but you never know. Shortening and recrowning is definitely one way to go. I would shoot it until I could no longer stand it, then go semi custom.

"it put most of them into 1-1.5" at 100 yards,"

Leave it alone, it couldn't love you any more.

I seriously doubt leaping will no no more than help.. If winchester will fix it then do it. As a rifle with a rough bore will be a hard sale down the road.. It would bug me also. ButI have several shooter rifles with rough spots and they shoot fine. I just can bring myself to put a whole lot of effort into them.

Generally you can hand lap stuff like that out but you should know what you are doing.

Did you bore scope it yet?

Not a gun smith but hand lapping a finished barrel takes a knowledgeable touch to do properly. Even then it is usually recommended to lop off at least an inch off the barrel.

Try Winchester first but if they shoot a test group they will send it back to you untouched and on your dime most likely.

I would try the Tubbs final finish with the bullets lubed before firing go easy maybe using only 3-5 of the courser ones. Tri Lube seems to get the abrasive action further down the barrel
(Zeddeker tip).

Afterward I would use Dyna bore coat or whatever it is called now. This has worked on really bad tomato stake barrels before.

If it still bothered me I would go ahead and lop 1.5 to 2" off the muzzle which is a sure fix.

I agree you need to know what your doing.

I took a course from a gunsmith to learn how to do it.

That being said - you want to lap the bad spot not the rest - and Ideally you'd get a nice even drag all the way down the barrel.

Fire lapping does more at the Throat end than the rest of the way down the barrel - how far down is your rough spot?

Man, a 24" 375 barrel? Lop it off.

Agree but the trilube oil does seem to get it farther down the barrel. Looking down the muzzle everything was shinier and felt smoother when running a patch down the bore.

Hand lapping would do it but is so risky on anything but an unfinished barrel or a clunker.

This is it.