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AR10 type bolt hold open issue / questions

Gunnersmate

Private
Minuteman
Oct 23, 2023
17
10
Albuquerque
I assembled my AR10 type rifle and test fired the rifle. All works well except the bolt hold open device IF I try to latch the bolt back with no magazine or remove the empty magazine, the bolt does not stay back.
I have two types of BHO's. One is original MILSPEC AR15 and the other a KAK enhanced .308 BHO.
The AR15 BHO can be set by hand with no magazine in place, not having the extension on the latch,it is a real pain to do.
The KAK cannot be set,the bolt slides over the "latch" with little effort but catches with the magazine follower until the magazine is removed .
I removed the BHO from the rifle and took close up photos of the two devices and you can see the KAK latch edge is clearly "rounded-off"more that the original AR15 type.
The original AR15 latch has a much more acute edge which grabs the milled portion of the bolt. The bolt has a really nice "stop" edge machined into it.
Both upper and lower receivers are a very nice tight fit together. No slop.
AR15 original
HO3.JPG

KAK Enhanced

HO2.JPG


I've tried several new BHO springs with no change. My buffer is not Too long. The buffer spring has be switched out with several other new RIFLE springs with no change.

HO1.JPG

Original on left,

HO4.JPG

Original on left.

HO5.JPG


KAK on right has extended manual portion for the thicker AR10 type receiver. A really nice feature.
My questions are can I machine down or file down the KAK "latch" edge to a sharper angle to allow a better "grab" of the bolt?
Or is there a better way to get the KAK latch to work with no magazine in place?
Thank you for any helpful info.
 
What specific brand lower do you have ?

And ,as you might know, there is no MilSpec guideline for LFAR's , so your model lower helps decide which bolt catch.

And the side you would like to file down, ( In your photo ) isn't where I would file... I would file the slight angle on the other / upper edge directly above your red arrow.