I am wanting to change from old, OLD, Lyman Tru-Lock bases and rings to Weaver type bases and rings on a VZ33 actioned rifle. The spacing of the tapped holes in the bridge is 0.425", as best I can measure it. The raised lip around the charging clip slot is still in place, and the Lyman rear base is 'sculptured' to fit up to it.

The Weaver chart specifies a No. 55 rear base for the S R Mauser. Can anyone tell me what the hole spacing of this base is? If it is NOT 0.425", does anyone know of any other brand of Weaver type rear base which would match?

I do have various pieces of Weaver type base blank to hand, and I could make a new rear base from some of this if I have to, but I'd sooner save myself the effort if there is something available off-the-shelf.

TIA
Red

I have a weaver #45 that is .5", dont know what the #55 measures.

redrover,

The 55 base has a hole spacing of 0.504 inches. Don't know of any weaver base with hole spacing closer than 0.504".

Mark

Thanks for supplying that information, Mark. It looks like I will be having to make a 'one-off' special for myself in the near future.

Red

If this is any help, I believe Brownell's can supply a blank bar of steel machined to Weaver specs.

Red,

Happy to try and help. Might want to double check with weaver directly as my base list is over 20years old.

Mark

Jason: Thanks for the advice, but I already have some alloy, Weaver-type base blank that I can utilise. Same upper profile as a Weaver No. 46 base, but a much deeper, flat-bottomed lower section. A bit of a chore to have to cut a piece of it to the correct height, shape the bottom of it to fit the profile of the bridge, drill and counter-sink it, etc, etc, but it can be done.

Mark: You are probably right. A few days ago, I went through my gunsmith's total stock of Weaver bases - dozens and dozens of them! He didn't have EVERY model they make (no No. 55, for example) but I didn't see anything even close to what I need. You saved me from odering a No. 55 and then finding that it was no use to me.

quote:

Originally posted by Mark Holycross:
redrover,

The 55 base has a hole spacing of 0.504 inches. Don't know of any weaver base with hole spacing closer than 0.504".

Mark

"Introduction to Modern Gunsmithing" by MacFarland, Harold E 1965, shows on page 231 in a Weavar mount spec list, the only centers closer than .504" is the Weaver # 41, #141, and #149 at .435".
These fit larger diameters, and could be re radiused if needed as they are all ~ .35" thick.

tnekkcc,

How many weaver mounts are in the spec list?
Does it give length, diamenter, thickness as well as hole spacing?
Do you know if the #41 base is still made? Just that the list I have from 1982 doesn't show it.

Mark

tnekkcc: Thanks for the pointer. I do have MacFarland’s book, but for some inexplicable reason, I forgot to look there when I was trying to locate specs. for Weaver bases. I see a No. 49 base on that list which also has a hole spacing of 0.435â€. I doubt that the No. 141 or 149 bases would be anything that I could use – it looks like they are/were for the old Weaver Pivot Mount.

Now to try to find out if either the No. 41 or 49 bases are still obtainable …

Mark: The chart in the book gives the length, hole spacing, diameter (presumably meaning the diameter the bottom of the base is cut to, not the diameter of the receiver the base is designed to fit on to) and thickness of bases No. 11 to No. 59.

Some of the ‘thickness’ measurements shown in MacFarland’s chart do not agree with actual samples I have to hand.

For example, for a #35 (front base, Rem 700) it shows a Thickness of 0.272, while my actual sample measures more like 0.222. Could just be a ‘typo’. (I didn’t remove the scope and take the bases off the rifle to measure them precisely) The thickness shown for the #36 (rear base, Rem 700) of 0.275 seems to be about right.

For a #46 (front base, Mauser 98) it shows a thickness of 0.350, while my actual sample measures more like 0.275. For a #45 (rear base, Mauser 98) it shows a thickness of 0.222, while my actual sample measures more like 0.46. For a #55 (rear base, small ring Mauser 98) it shows a thickness of 0.310. I don’t have one of these to measure, but the stated thickness doesn’t appear to jibe with the either the stated or actual thickness of the #45, as the SR is only 0.10 to 0.11 smaller in diameter than the LR. It looks like there could be both model variations and errors involved here.

From what I have been able to check, so far, I would treat all of MacFarland’s thickness measurements as suspect.

I recently found a ‘Base Selector Chart’ (for Weaver bases, that is) on a local gunshop’s web site. (nothing at all like that on Weaver’s own web site – it doesn’t even MENTION rings and bases, that I could see!) This chart lists all the most common rifles, and some pretty rare ones, too. Nos. 41 and 49 bases do not feature anywhere on the chart, which is not too encouraging, but I’ll make some phone calls tomorrow. (with my fingers crossed!)