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Extended take down pins


gmoore57

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So, I bought my first .308 AR; a Ruger SR-762.  I'm happy with the rifle and I especially like the adjustable gas system.  Here is my parts question. Does anyone know if there is a set of extended take down pins available for this rifle?  I bought a set marked DPM and they are too big in diameter and the front pin is too short also.  So I'll ask again: does anyone know of a set of extended TDPs that will work in the SR-762?

 

Also, does anyone else need the DPM set I bought for their .308 AR?

 

Thanks for the help,

 

Gary

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If Matrix is making the receivers for Ruger it looks like the Armalite AR10 take down pins would be the same dimensions.  At least that is what my research has indicated. Does anyone know who makes extended pins for the Armalite?

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Does anyone know who makes extended pins for the Armalite?

 

The same people that make extended pins for DPMS-based 308 rifles - the Armalite and DPMS pins are the same dimensions.

 

As I said before - get me measurements of your pins, and I might be able to help you out.

 

 

Gary, measure the diameter and working length of your takedown pin.  I might have one that will work, if the dimensions are the same.  I don't have any pivot pins, though.
Edited by 98Z5V
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As I said before - get me measurements of your pins, and I might be able to help you out.

The Ruger pins are .275" diameter (DPM = .277" and won't go in the holes).  The pivot pin is 1.370" (DPM = 1.564") and the take down pin is 1.165" (DPM = 1.093").  I'm no machinist, but these are the #s I came up with using my vernier calipers.  The lengths are within a couple of 1/1000" in any event and the diameters are dead nuts.

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The Ruger pins are .275" diameter (DPM = .277" and won't go in the holes).  The pivot pin is 1.370" (DPM = 1.564") and the take down pin is 1.165" (DPM = 1.093").  I'm no machinist, but these are the #s I came up with using my vernier calipers.  The lengths are within a couple of 1/1000" in any event and the diameters are dead nuts.

 

i've got a standard DPMS pivot pin here that's 1.511" long, and 0.276" diameter.  So, too much length, but you can work with a different diameter.  If your receiver pin holes are 0.275", then you can bring them up to 0.277" with a "J" sized drill bit, and up to 0.281" with a "K" sized drill bit.  I think you'd be fine with the J bit, at 0.277".

 

If you're running a pivot pin that's 0.150" longer, it's easier to get it moving and pop it open.  The Battle Arms Development Enhanced Pins were designed 0.070" longer over stock AR15 pins, for just that very reason.  You don't even notice the extra 0.070" honestly, and an extra 0.150" would not be a hindrance in any way.

 

Pivot pin solved.

 

The DPMS extended pins that I have are 1.073" in length, 0.275" diameter.  0.090" shorter than the takedown that you have.  Might be hard to get moving, but it's in both sides of the receiver, in a non-stressed area.  It's captured by the spring/detent in the closed position, and not going anywhere.  I have 5 of them sitting here...

 

The Rock River extended takedown pins I have are 1.204" in length, and 0.273" in diameter.  That would be about an extra 0.060" in length (get it moving easier), and you wouldn't have to touch the holes to fit it in your lower.  I have 5 of these sitting here...

 

So, now that you've posted the measurements, are you ready to experiment?  Tell me if you want something sent, and PM me your address, and I'll send you the parts you need to experiment.

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 So the Pivot Pin is shorter than a DPMS & the Take Down Pin is longer than a DPMS .

 

 With the Pins being 0.275" , a smaller diameter than the 0.277" DPMS Pins ?

 

  Ya got me  <dontknow>  sounds Proprietary for Ruger Receivers . 

You are exactly right in your observations.  It seemed odd to me, but that is what they did.

 

i've got a standard DPMS pivot pin here that's 1.511" long, and 0.276" diameter.  So, too much length, but you can work with a different diameter.  If your receiver pin holes are 0.275", then you can bring them up to 0.277" with a "J" sized drill bit, and up to 0.281" with a "K" sized drill bit.  I think you'd be fine with the J bit, at 0.277".

 

If you're running a pivot pin that's 0.150" longer, it's easier to get it moving and pop it open.  The Battle Arms Development Enhanced Pins were designed 0.070" longer over stock AR15 pins, for just that very reason.  You don't even notice the extra 0.070" honestly, and an extra 0.150" would not be a hindrance in any way.

 

Pivot pin solved.

 

The DPMS extended pins that I have are 1.073" in length, 0.275" diameter.  0.090" shorter than the takedown that you have.  Might be hard to get moving, but it's in both sides of the receiver, in a non-stressed area.  It's captured by the spring/detent in the closed position, and not going anywhere.  I have 5 of them sitting here...

 

The Rock River extended takedown pins I have are 1.204" in length, and 0.273" in diameter.  That would be about an extra 0.060" in length (get it moving easier), and you wouldn't have to touch the holes to fit it in your lower.  I have 5 of these sitting here...

 

So, now that you've posted the measurements, are you ready to experiment?  Tell me if you want something sent, and PM me your address, and I'll send you the parts you need to experiment.

I'm ready to give it a try.  I think the Rock River TDP is the one to go with.  The extra length will help getting the pin to move like you suggested.  The larger diameter pivot pin might just fit.  The DPM pins I bought are just a little too big in diameter so I'm hoping the one you have will go in without galling.  I'll make the holes bigger if need be.

 

Do you have any need for these DPM pins I bought?  I'd certainly be happy to send them along.  In any event, what do you want for your pins?  I really appreciate your help.  This is a great site.  I'm sort of itching to build an AR-10 from scratch and now I know where to go to get any information I might need.   I will PM you my contact information.  Please let me know if there is anything else you need from me.  

 

Thanks everyone,

 

Gary 

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  This may be a really stupid question , but why bother changing them when all you need is something to push them out with ? I use a plastic pen shell or a plastic punch . I would not alter the Receivers pin holes , It would not be a problem to alter a Pin size , they can be turned down or even made to your spec's , if you so choose.

  The placement of the detent notch in the grove of the Pin would have to match to retain the pin in fully closed position , also . Experiment with ,as was said , the least expensive component ( Pins )

  There are those here that can Machine you pretty much anything you need , if you have good spec's .

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  This may be a really stupid question , but why bother changing them when all you need is something to push them out with ? I use a plastic pen shell or a plastic punch . I would not alter the Receivers pin holes , It would not be a problem to alter a Pin size , they can be turned down or even made to your spec's , if you so choose.

  The placement of the detent notch in the grove of the Pin would have to match to retain the pin in fully closed position , also . Experiment with ,as was said , the least expensive component ( Pins )

  There are those here that can Machine you pretty much anything you need , if you have good spec's .

That is not a stupid question at all.  I just have found that replacing the flat heads on the take down pins makes it a much easier job to get an ar style rifle apart.  I have ripped off my finger nails because I'm too stupid to find my plastic or brass punches.  It's really just a simple change to put a TDP with an extended head on it so that I don't have to worry about getting the thing apart.

 

 I think your point about not modifying the receiver is a good one.  I really have to give that some thought.  When I started this endeavor I didn't realize that the .308 ARs were very different from each other.  I figured they would be "mil-spec" like the .223s.  I'm going to experiment with this and with the help of the people on this board (especially 98Z5V) I'll find something that works...I hope. 

 

If I have to get someone to machine them for me I will give them good specs.  The best way is probably to send them the factory pins so they can reproduce the shaft dimensions with a bigger head, but I'm not sure anyone wants to mess with this for one set.  Now if we could get a few people interested that might be a different story.

 

Thanks for your thoughts on this,

 

Gary

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Emery cloth around the pin, grit towards the pin, will take off enough material to allow it to fit. Works on 1911s.

I was thinking the same thing. The difference in diameter is only 2 thousandths, right? That'd be the cheapest and easiest thing to try.

FWIW, my pins almost sit flush with the receiver, so I just use chamber flags; http://www.midwayusa.com/product/1116263619/tapco-rifle-chamber-safety-flag-tool?cm_vc=ProductFinding

They come 6 to a pack, so no problem if one breaks.

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