AR15 Worn Pin Holes

[iraiam]

I have an old Colt Match Target HBAR that is showing it's age. The hole in the receiver for the hammer pin has wear in it, the pin is kind of floating and spins with the hammer every time now, which will likely increase the rate of wear.

I have ordered an anti-rotating pin kit for it.

anyone know of another fix, besides replacing the lower?

 

[g.willikers]

The usual fix for this kind of thing, is to bush the old holes for the proper sized pin that fits the hammer and trigger.

 

[Recoiljunky]

i would agree. take it to your local machine shop or gunsmith and have them sleeve the pin holes anyone with a milling machine should beable to acomplish this

 

[HiBC]

And,remember to check how much a YHM or Aero lower will cost.It won't say Colt,but it won't be wore out and bushed,either.

Machine shops generally will have a higher flat rate than ,say auto or boat mechanics.

Do be careful about pin diameters,both Takedown and hinge,and trigger/hammer.Some Colts were different.

 

[iraiam]

I can do the machine work myself, just a matter of figuring out how I want to do it. The anti-rotating pins will suffice for the time being I suppose.

I have a couple spare receivers, but I would rather save this one from further wear, it has not affected anything yet but mechanical wear does not stop by itself.

My Colt has the "big" FCG pins 0.170", the the takedown pin and pivot pin are standard size.

 

[Rottweiler]

It would probably be cheaper just to replace the lower

 

[BoogieMan]

You can order bushings (or make them) from places like mcmaster carr (mcmaster.com) then you simply open the holes up to press the bushings in. For the hassle and probability that you will miss-align the holes I would suggest buying a lower. Blem lowers will run you $79 new $120ish. Not worth the cost of bushings and time to do the job.

 

[HiBC]

If you do bush it,you have a given wall thickness in the receiver.Think about the relationship of the diameter to the wall thickness which is the length vs dia of your bushing.

I think I would go for bushing down to .154 pins and get a new,common hammer and pins vs the .170 original.

But,Im still in the "new lower" camp.

If you can find a design drawing,setup based on a location from whatever datums they used to design the reveiver,then bore the holes with a small carbide end mill.That black anodizing is hard!expect it to dull your cutter.

If you try a drill/reamer trick,the drill will deflect to the worn hole.Boring with an end mill will give you a location.

If they are only a little loose,and you want to try a patch job,supplemented by your new,anti-rotating pins,get about a .250 dia ball bearing,support the receiver real well,set the ball on the worn hole and rap it with a ball pein.

You will do something like a primer crimp.The hole will get a little tighter.

If you get fancy,use a small center drill to put a dimple in a bar so the ball wont roll off,put the bar in a vise,reach the ball and bar inside the receiver,and use a clean,square ended punch on the outside to crimp the hole on the inside the receiver.

If that doesn't work,cut it for bushings.

Another option,negotiate with your anti-rotation pin folks.Tell them,for worn guns,the ought to offer a kit of1.5 mm oversize pins and a hammer to match,and please make you one.