I have had 6/48s shear off, I have twisted them apart on more than one ocassion and especially with torx, I can really get down on those puppies...

Trouble with a lot of gunsmith, they are too busy to go out into the field and use guns and they get some wierd ideas IMO...

I like 8-40s with screws and bases properly glassed on the rifle. I'd weld the little bastards if I could...

I am talking about big bores mostly but it sure doesn't hurt to do them all in 8-40s IMO...If one is satisfied with 6-48s then use them, if you ever have a problem then consider change...

I just ran across tis thread again as well.
I remember postihng once here, but the second post is not from me. I would know far better than to ask if JBelk went from the first screw LOL
I aligh always on the mill and from the barrel centerline. It gets em pretty close.

The Real Celt

There are a couple of good reasons to go with 8X40s.

Yes, they are stronger than 6X48s, but to me, the main reason is to solve alignment problems. It's not at all unusual for factory scope base holes to be way off center to begin with. You can even exacerbate the problem by squaring the front of the action as part of the blueprinting process.

Properly done, enlarging the holes to 8X40 can eliminate these discrepancies and increase strength at the same time. I highly recommend it, and I see no good reason NOT to have the proceedure done.

I have a .30-06 that Darrell Holland built for me quite some time ago. This rifle has been a frustrating collection of little problems from the beginning. One of it's main glitchs is that, even though the receiver was blueprinted, the scope base holes are factory-original, and are way, way out of alignment with the axis of the bore. Windage screw-type scope bases provide an unsatisfactory solution, because one side ends up being backed so far out that only a couple of threads make purchase with the base.

When I get around to it, I'm sending the rifle to Mark Penrod so that he can enlarge the holes to 8X40 and eliminate most, if not all of the alignment problems, plus make proper bases that really fit. This stuff should have been taken care of to begin with, but for whatever reason was not.

AD

Ditto what the "real" Celt1 said.....
Charlie

Allen,

That is an interesting point you raise.

As to strength I have never had any trouble with 6 X 48 and epoxied bases and I have shot a lot of rounds from the 378s, 458s and 460s and a bag of lead shot behind the gun won't make any difference to scope mounts apart from the fatc that it allows a lot more shots to be fired.

If I ever felt the need for bigger screws then I would have the bases sweated to the reciever.

In my experience and with bases glued on, all scope mount problems (in terms of strength etc.) involve the attachment of the ring to the base.

Mike

A few years back, I had a rifle put together on a LH Model 70 Classic stainless action. These actions are a fairly rare item but I decided to put this thing in a certain gunsmiths hands to be massaged into, what I thought would be, something better. One of the things I requested was to have the screw holes opened up to 8X40 on the centerline of the bore. The holes were crooked, I new it, and wanted things fixed. He opened them up all right but he followed the centerline of the existing holes. With a set of custom bases built by Lex Webernick, I couldn�t get anywhere near the target. I called the gunsmith about it and he gave me some song and dance about having to follow the existing holes, saying that doing it any other way was impossible.

This screw up cost me a pile of money to make right. So unless it�s done right I say forget it. Have the bridge and receiver ring recontoured to fit the bases while you�re at it. An improper contour can throw things out of whack as well.

In a recent article written by Patrick Sweeny, he extolled the virtues of 8X40 screws. Fine. But then he went on to ask all arms manufactures to send their wares from the factory so equipped. A stupid request at best, leaving those who care needing to go to greater lengths to fix inevitable factory mistakes.

Chuck

One of the reasons I like built up Mausers, there actions can be surface ground, properly lined up and D&T with hand fitted bases..This also makes QD rings return to zero much better than off center stuff will...but I would go with 8-40s anyway, it can't hurt a thing..Not all my guns have 8-40s and I've only had a couple of 6-48s pop for whatever reason, but I can sure twist one in too if I am not real careful, especially the new Torx screws and I have seen them dent a scope with improper rings..

If I had a gun with off center holes I'd dump it at the nearest gun show or send it back to the factory for replacement, I don't want it fixed, I want it replaced...

Lots of claims that a hole can be straightened and perhaps some can, but some cannot as a drill will follow a hole sure as hell, and if that hole is drifted then it wont go straight, and I don't care what you chuck it up in....What you may end up with is a "straighter" hole, not a straight hole. At least thats what I think.

If a gunsmith won't or can't accomplish this within sane parameters I'm more than happy to go elsewhere.

Chuck