Adding Arca rail to a3-5

03machstock

Sergeant of the Hide
Full Member
Minuteman
Oct 16, 2021
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Pennsylvania
Looking to add a full length Arca rail in place of my pic rail on my McMillan a3-5 to mount to a tripod, bipod, etc. I was leaning towards area 419 and I could fit a 10” before the little kick down to the bottom metal. I saw they make a spacer for a manners t6 that has a similar size bump based off pictures, If that fit and I used the action screw I could fit a 12”. Anyone know if that spacer would fit or could be easily modified to fit? Would using the action screw to mount the back of the Arca rail effect accuracy when clamping in and out and banging off of barricades? Should I say screw it and just mount the 10” on the flat part?
 

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I've added Arca rails, with and without the stepdown, that used longer action screws that went through the rail. One rifle turned out great and shot the same as before the the rail. The other rifle had terrible accuracy afterwards and I ended up taking the rail off. If I were in your position, I would add t-nuts to the stock and use a rail that stops before the step down.
 
I've added Arca rails, with and without the stepdown, that used longer action screws that went through the rail. One rifle turned out great and shot the same as before the the rail. The other rifle had terrible accuracy afterwards and I ended up taking the rail off. If I were in your position, I would add t-nuts to the stock and use a rail that stops before the step down.
This is exactly what I was looking for, thanks!
 
I’ve been looking at the same thing. I have decided on a 12 inch and just allow the excess to stick out the front, which will ultimately allow to push bipod out a touch further. Or like you said , you could just cut it.
 
I’ve been looking at the same thing. I have decided on a 12 inch and just allow the excess to stick out the front, which will ultimately allow to push bipod out a touch further. Or like you said , you could just cut it.
I ordered the 10” as the hinging over look hasn’t grown on me yet. If I don’t like the 10” I’ll order the 12 and do the same and just throw the 10” on something else.
 
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Looking to add a full length Arca rail in place of my pic rail on my McMillan a3-5 to mount to a tripod, bipod, etc. I was leaning towards area 419 and I could fit a 10” before the little kick down to the bottom metal. I saw they make a spacer for a manners t6 that has a similar size bump based off pictures, If that fit and I used the action screw I could fit a 12”. Anyone know if that spacer would fit or could be easily modified to fit? Would using the action screw to mount the back of the Arca rail effect accuracy when clamping in and out and banging off of barricades? Should I say screw it and just mount the 10” on the flat part?
Did you ever end up proceeding with this? How'd it turn out?
 
Thread resurrection.

What's the preferred method of attachment these days?

My McBros A3 stock has 2 sling swivels up front and the action screw in the back. Should I utilize those holes or use T-nuts?
 
I did 1 extra t nut, utilizing the 2 screws from the pic rail up front. However, I took the Arca off. I hated it. Not the Arca itself, I love the idea and versatility of it. But on this stock with the thinner forend, it was all you could feel when grabbing the gun because it stuck out further than the stock itself, and dug into your hand. It probably wouldn’t have been bad or noticeable on an a5 because of the beaver tail wide foregrip, but on this stock it wasn’t for me.