Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
1/28/2007 1:20:46 PM EDT
I was wondering if one of you guys could post some detailed pictures
of the modifications that are made to your straight pull AR BCG's
and upper receivers.
I'm thinking of putting one of these together for use as a teaching tool
with new shooters. I know nobody has more experience with this
format than you guys.
Thanks in advance for the help.
1/28/2007 2:09:12 PM EDT
[#1]
Hi, I've got loads of pics and advice, but it's getting late and it will be a long post so I'll tackle it tomorrow.

Check back then

Mark
1/29/2007 3:55:04 AM EDT
[#2]
Why would you want to do this?  We don't have a choice
1/29/2007 4:12:34 AM EDT
[#3]
It's the reason the cadet rifles were only issued in straight pull (at first) as it's definitely easier to make a mistake/ad/nd with a self-loader.
1/29/2007 5:34:24 AM EDT
[#4]

Quoted:
It's the reason the cadet rifles were only issued in straight pull (at first) as it's definitely easier to make a mistake/ad/nd with a self-loader.


That wasn't the reason, storage security issues drove that decision.
1/29/2007 1:50:35 PM EDT
[#5]
OK,
I said I'd post something tonight, so here goes.
I've done so many of these conversions I've lost count, but it must be somewhere between 75-100

There are various ways to do the mods, depending on what type of receiver you use.

The simplest way is to use a DPMS Lo Pro receiver. These don't have a forward assist or case deflector on them so the machining is pretty straightforward

This one was a DPMS Hi-Rider that we cut the rail off and fitted an extended one.
This receiver is actually from Southern Gun and the slot work is theirs. All I did was plug the existing hole in the carrier and make a new handle for it.
I don't like this slot placement as although all you are doing is extending the original ejection port, I feel thet the handle ends up sitting at the wrong angle.

Here is another DPMS upper before any work is carried out




This is an Ameetec upper. Like some of the DPMS uppers, it has l/h side charging


As you can see, I prefer to lower the ejection port. You do this until the bottom rail on the carrier can just be seen.
These receivers are easy to work on as again, there is no forward assist and the phoney case deflector can be milled straight through and doesn't need to be removed.
I have found these receivers to be a little soft.

I must add that when you do any of these mods and make a cocking handle for it, you have to machine a radius on to the mounting face of the handle to match the radius on the carrier.  A 25mm milling cutter does it just fine but you will have to adjust the position until you get the handle sitting at the correct angle.

While we're talking about carriers, i must make you aware that the carriers can be as hard as nails, and I've lost more than a few drills and taps on them.
Once you break the surface, it's ok, and one of the best things I've found for getting through the surface is a good old carbide masonry bit

The problem with the forward assist is that the hole means that you have to machine the slot further back than the ideal
Here is a receiver that's had all the lumps and bumps taken off before slotting

You can see the forward assist hole

Here it is after slotting


And here it is after making and fitting the handle


I used to use a polyurethane paint to finish them, but now I powder coat.


This is my Highpower rifle. I modified this one 3 years ago and it's still going strong


This is another one I did


This is one of the earlier ones


Another shot of the DPMS upper


And finally, this is one I did for some Gangsta's


Mark
1/29/2007 2:21:34 PM EDT
[#6]

Quoted:
Why would you want to do this?  We don't have a choice


I understand your point, but not every
firearm I own is a semi-auto.

I have a couple of reasons why I would want to do this.
I teach a few different safety classes, and I think a straight pull AR
might be a great tool.
With younger shooters I think this would lend
it self to much more deliberate shooting.
Also, I have assembled AR's in many different configurations,
why not this one?
-Ralph

1/29/2007 2:51:32 PM EDT
[#7]
Thanks for the pictures and info Streetfighter.
It's about what I thought it would be.

What depth are you drilling and taping the carrier to?
1/29/2007 2:54:28 PM EDT
[#8]
Drill right through into the bolt raceway, then use a Dremel to take the burrs off

Mark

Oh, screw is 6mm or 1/4"
1/30/2007 11:15:03 AM EDT
[#9]
Great Scott! that AR appears to be missing the gas return tube!
1/30/2007 11:24:44 AM EDT
[#10]

Quoted:
Great Scott! that AR appears to be missing the gas return tube!



It's missing a lot more than that
1/30/2007 12:47:17 PM EDT
[#11]
No anodising Mark?


eta, i may have just the drill bit for this application in my tool box Mark,

sell centreing solid carbide ticn coated, 5.1mm we used to use them for drilling en24 to tap using speacial high torque taps, i cant rember if i handed tham back into the stores or not... i'll check when i get home.
1/30/2007 12:58:56 PM EDT
[#12]

Quoted:
No anodising Mark?


eta, i may have just the drill bit for this application in my tool box Mark,

sell centreing solid carbide ticn coated, 5.1mm we used to use them for drilling en24 to tap using speacial high torque taps, i cant rember if i handed tham back into the stores or not... i'll check when i get home.


The anodizing's the pain as all the old finish has to be stripped off and as it eats into the surface, the dimensions change.
I've had no problems with the powder coating
1/30/2007 3:26:25 PM EDT
[#13]
ooh! ooh! anodizing = pink
1/31/2007 4:48:21 AM EDT
[#14]
the anodizing could be chemically stripped off with the bore masked to prevent stripping,