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jeepcreep927 07-07-2010 06:19 PM

Scope Base Holes Galore
I picked up three M98 receivers for projects. The receivers are in great shape however the rear most holes for the rear scope bases on all three are drilled about 1/16" too far forward to allign properly with the bases. I have tried three different brands of bases with Warne coming the closest (1/16" off).

I had thought of either having the bases themselves welded and re-drilled to match the receiver or having the rear most hole in the receiver welded, TIG I would think, and redrilled and tapped. If there would be no adverse effects I would prefer to do it that way but I am not a weldor so I don't know how much heat transfer there would be with TIG, and if would compromise the integrity of the receiver, or if it would even matter as it's the rear bridge and not subject to a lot of pressure. Any suggestions?

And, if it would be ok to do this, any of you that are gunsmiths and/ or weldors that could do this, PM me and I'll send you the receivers and a money order for your fee since I can't find anyone locally. Thanks.

willshoum 07-07-2010 07:02 PM

Bad positioning
Tig welding carries a lot of heat. What you might try is useing screws and loctite then re drill an tap. If you go with welding make sure you put a brass plug or carbon rod in the hole, and have the hole tappered for the welding. The bore past the hole to be drilled and tapped is what needs to be protected, wrap parts to be welded in insulation then air cooled. Pm me if you don't under stand. Will in da Swamp

Fisherking 07-08-2010 01:53 PM

Brownells sells a great past for welding so that heat is not transferd past that point . I was sceptical about it at first but the stuff realy works. Tig welding caries about the least amount of heat compared to mig or stick. Wils of the swamp was saying to insert a brass or carbon rod. I'm asuming that he is talking about a heat sink to draw heat away from the area that you don't want to lose hardness or warpage. I live in Northern Ontario so probably a little far to ship with cusoms the way they are.
Good luck with your build and keep us poasted.

cpttango30 07-08-2010 04:41 PM

I decent gunsmith should be able to fill the old holes.

Have you thought about using a 2 piece mount then you don't have to worry about the hole spacing.

stalkingbear 07-08-2010 05:42 PM

I'd advise to fill in the holes and redrill the receiver. Be SURE to use mild steel when you fill up the holes or a regular drill bit won't even penetrate the fill. It's not hard to do, you should be able to fill in the holes and lay out the holes in your drill press. What you could do after filling in the holes is use the front 2 screws to attach the base, then drill the center of the holes in the base after starting them correctly. I use a mig welder and you won't lose heat treat if you do it right the 1st time.

jeepcreep927 07-08-2010 11:17 PM

Thanks all for your replys. I have a tub of the paste from Brownells and I think I'll get an aluminum or brass heat sink and give it a go with MIG and redrill. Thanks again.

TheOldMan 07-20-2010 12:58 PM

MidwayUSA Videos
Youtube has a video library of gunsmithing techniques presented by the founder and CEO of MidwayUSA. One of the videos is on how to fill in old scope mount holes without welding. Very simple technique that any do-it-yourselfer can accomplish.

I'd personally shy away from welding on the reciever...

stalkingbear 07-20-2010 05:58 PM

I've welded receivers and bolt handles with no bad results for a lot of years. It's all in prep, attention to detail, and doing it the right way to start with.

jeepcreep927 07-20-2010 09:42 PM

I saw the videos on Youtube about using the peened screws but I will need to drill and tap partially overlapping the hole that needs to be filled so I am looking more toward welding. Thanks for the tip though.

I need three of these receivers welded and re-drilled/ tapped as well as short chambered barrels installed and finish reamed. Could you define your "semi-retired" status for me as I can't find a gunsmith locally and would enlist your services if you are willing. Around here, apparently saying you're a gunsmith means you can screw on scope bases and install sling swivels. PM me if you might be interested. Thanks.

stalkingbear 07-21-2010 02:19 AM

PM sent jeep.

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