Ok all I could use some help. I installed a PDQ ambi bolt catch in one rifle with a roll pin. I did not want to keep driving the roll pin while test fitting it. I tried my best and after I thought I had it installed the pin. Dang it has a little drag still and is inconsistent locking the bolt back on empty magazine. If give a tiny amount of pressure to assist it locks every time. What is everyone using to temporary install in place of the roll pins and testing so I don't just beat it up? Any tips and tricks on the milling for the PDQ? I have it perfectly square with a super fine file and polished with cloth dremel/rouge and re-blacked. Maybe more bevel on the right side notch edges? I will take it apart again, and I don't want to use another rifle this weekend for a training I'm putting on.
PDQ Ambi Bolt Catch
- Thread starter Reelamin
- Start date
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I figured out what my issue is. The dang Dust Cover hits it, and will not allow it to raise. I checked it with me blocking the door, and it locked back every time on four diff. mags. I went so far testing I removed the door and any amount of spring pressure would interfere. Only suggestion from the vendor was try a plastic door. When I explained in detail what I had done he then referred me to the manufacturer. I am still waiting for a response. I used my brass catcher to stop the door and it ran perfect in two days of shooting. Any suggestions on how to still have a working fully fitting dust cover and not interfere with the PDQ?
@ARlife4me Thanks for the suggestion. Simple and so obvious now. I tried a drill bit and it was too long. Lots of fishing line up to 150#, will try that next.
@ARlife4me Thanks for the suggestion. Simple and so obvious now. I tried a drill bit and it was too long. Lots of fishing line up to 150#, will try that next.
Dang! I missed the ambi part. Was it an add-on to the bolt catch or a 1-piece ambi? Some interfere behind the catch (externaly above the roll pin) and keep the bolt in catch position. I was reading the post on a phone instead of a larger screen. I miss slight info like that at times unless in better light or less glare. Glad it's fixed. I just looked up the catch type and I have 1 of those on an AP lower. Makes sense on that type getting interference with the dust cover. Luckily the 1 I have doesn't interfere, but if just forward enough it will.
cohunt
Well-Known Member
Years ago I installed the tbb pdq in an 80% that i have-- mine was a prototype nib coated mim version. It works great, no problems--- dust cover does not affect it at all. Still working with no issues today.
Have you tried different magazines? The magazine follower and spring push up on the pdq catch when mag is empty so maybe your follower is worn or spring is weak? Just a thought.
I used a small diameter mill bit the size of the slot in my drill press with 2 way cross slide vice to mill it-- after I milled the slot I dressed it with a small distributor points file to clean off all the machining marks and make it smooth .
Have you tried different magazines? The magazine follower and spring push up on the pdq catch when mag is empty so maybe your follower is worn or spring is weak? Just a thought.
I used a small diameter mill bit the size of the slot in my drill press with 2 way cross slide vice to mill it-- after I milled the slot I dressed it with a small distributor points file to clean off all the machining marks and make it smooth .
Here are some photos of what was done for milling on a Ruger and Aero Receiver. No it was then fine filed, and polished with felt/rouge then Aluminum Blacked. Also, some photos of the Ruger door hitting the PDQ. The Aero enhanced upper door also hits exactly like the Ruger. The strength stamped rib is the point of contact, and if it was hammered flat door contact would then occur over a much wider section of door/PDQ. I'm not a machinist and my measurements show I would have to remove a huge amount of the PDQ arm to make it paper thin, or remove a portion of the door then exposing the chamber. The photos of the door on the PDQ show it when PDQ is down and when it is up with the bolt stopped. We will get this figured out and I will share my end result.
@ARlife4me ...laughing with you on the phone and screwing up. I do it all the time x100 brother!!! Yes it is/was a add on or replacement Ambidextrous Bolt Catch/Release. Works perfectly if the door is removed.
@cohunt Thanks for the information. Yes, lots of magazines from Old GI, GI with new Spring/Follower, Mag Pul 2,3, cheep junk, and brand new Mag Pul. Does not matter if door is on causes it to not work 99% of time, and works perfectly as intended when door removed or blocked from contact.
Yes I forgot the pics....here they are
@ARlife4me ...laughing with you on the phone and screwing up. I do it all the time x100 brother!!! Yes it is/was a add on or replacement Ambidextrous Bolt Catch/Release. Works perfectly if the door is removed.
@cohunt Thanks for the information. Yes, lots of magazines from Old GI, GI with new Spring/Follower, Mag Pul 2,3, cheep junk, and brand new Mag Pul. Does not matter if door is on causes it to not work 99% of time, and works perfectly as intended when door removed or blocked from contact.
Yes I forgot the pics....here they are
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Dang! I missed the ambi part. Was it an add-on to the bolt catch or a 1-piece ambi? Some interfere behind the catch (externaly above the roll pin) and keep the bolt in catch position. I was reading the post on a phone instead of a larger screen. I miss slight info like that at times unless in better light or less glare. Glad it's fixed. I just looked up the catch type and I have 1 of those on an AP lower. Makes sense on that type getting interference with the dust cover. Luckily the 1 I have doesn't interfere, but if just forward enough it will.
cohunt
Well-Known Member
Machining looks pretty rough to me-- did you smooth it out after that?
Yep for sure that was the final before smoothing, rounding edges, polishing, black. Thing works perfect with no door on upper or blocking it. I talked to someone at the manufacturer and they will get back to me. Just mentioned as a thought maybe a stronger spring for stop would overcome door. We will see how it goes. I'm not super interested in driving roll pin in and out 50 times. May switch over to the Aero and see how changes go.
cohunt
Well-Known Member
I used a 4 flute square end milling bit-- I can take a pic of mine to see how they compare--- I know you said it's your dust cover, but I dont have any issues with my dust cover--- something has to be different
Well, I am getting the new poor customer service treatment. Called and talked to them again, and feel like I am getting the shine on treatment. The AR15 gun work is new to me. Anyone know what spring would have less tension for the bolt stop detent. More pressure would cause the problem to be worse, and I'll take the risk of it bouncing up while firing it.
The spring pressure keeps it down. When the mag is empty the bolt catch will engage and holt the bolt open. You need 2 parts for the bolt catch (bolt catch spring and bolt catch plunger). With catch removed insert the spring then the plunger with catch last. IF you are testing without roll pin (proper 1) it can have enough play for it to NOT function correctly.
