Mark I bolt stop

bpratl · Post by **bpratl** » Mon Apr 13, 2009 8:05 pm

Has anyone tried to rethrofit a Mark II Stop Bolt bracket and a Bolt Release bracket in a Mark I frame? It looks like minor modification to the frame may be possible.

Post by **Bullseye** » Mon Apr 13, 2009 8:22 pm

Yes it has been done with success on an A-100 framed Mark I/Standard. It takes a few cuts to make the bolt release cut and the mag follower slot has to be extended. The toughest part is drilling the front lug for the bolt stop plunger. Some folks have come up with a piano spring device for this function. Here's one that's been modified.

R,
Bullseye

bpratl · Post by **bpratl** » Mon Apr 13, 2009 10:31 pm

Thanks for the info.......I do have a A-100 frame so I will order the parts and give it a try and post the results when complete.

Post by **Bullseye** » Tue Apr 14, 2009 11:35 am

You will also have to modify the underside of the receiver for the bolt stop. Milling a bolt stop slot is essential. Here's a picture of the slot on the underside of the receiver.

R,
Bullseye

bpratl · Post by **bpratl** » Wed Apr 15, 2009 5:38 am

Bullseye wrote: Milling a bolt stop slot is essential. Bullseye

Bullseye...Thanks again for update. I do have a small verticial mill so this is not a problem.

_____________________________________________________________

Bob

bpratl · Post by **bpratl** » Sun Apr 19, 2009 8:36 am

Received and installed the parts in the modified receiver and frame assembly. The upgrade works great. I am still having a little problem in finding a good bolt stop bracket spring setup.

Post by **Bullseye** » Sun Apr 19, 2009 8:23 pm

Sounds good I'm looking forward to seeing the pictures of your modification.

R,
Bullseye

bpratl · Post by **bpratl** » Sun Apr 19, 2009 9:30 pm

I did some more modifications as follows and it seems to function OK now.
As I could not drill the receiver dovetail I modified the Bolt Stop Bracket to accept a small spring. A slight offset prevented the spring from hanging up on the frame as can be seen in the photos.

Post by **Bullseye** » Mon Apr 20, 2009 7:00 am

That looks like a relatively simple solution to the spring problem. I like your ingenuity for the modification.

R,
Bullseye

gunsmither · Post by **gunsmither** » Fri May 08, 2009 8:07 pm

Great idea on the spring bpratl ! I've done two conversions; one with a factory style plunger, and one with a thin spring wire milled into a slot in the top edge of the hold open gizmo.

I built a drill jig to precisely drill for the factory parts, but that will only work on certain frames; can't recall which ones exactly. Your idea with the coil spring is the easiest yet that I've seen. Thanks very much for sharing it, as I have another MKI to convert one of these days, and I will likely use your method.

Great job! Joe

bpratl · Post by **bpratl** » Sat May 09, 2009 6:28 am

Thanks. I have shot quite a few rounds since the modification without any problems.

GunTalk-Online.com

Mark I bolt stop

Mark I bolt stop

Great idea!