Jump to content
308AR.com Community
  • Visit Brownells
  • Visit AR15 Builder
  • Visit
  • Visit Site
  • Visit Beachin Tactical
  • Visit
  • Visit Ballistic Advantage
  • Visit Aero Precision
  • Visit Cabelas
  • Visit Faxon
COBrien

PTG "AR-10" Upper Receiver Lapping Tool

Recommended Posts

Working on building up my CSASS-type rifle, and realized I might need/want to lap the front of the upper receiver. This is a DPMS-pattern build.

PTG makes an "AR-10" upper receiver lapping tool...

http://pacifictoolandgauge.com/ar-tools/10318-ar-15-upper-receiver-lapping-tool.html

If this is, truly, an AR-10 tool, is there any reason (I.D. of the receiver, specifically) it shouldn't work for an LR-308 pattern receiver?

Share this post


Link to post
Share on other sites

I have used that tool for a Matrix and Fulton Armory uppers, both LR-308's, with excellent results. The Fulton might not count as it was very even to start, more confirmed it was square than squared it.

8 minutes ago, COBrien said:

If this is, truly, an AR-10 tool, is there any reason (I.D. of the receiver, specifically) it shouldn't work for an LR-308 pattern receiver?

 

Share this post


Link to post
Share on other sites
Just now, jtallen83 said:

I have used that tool for a Matrix and Fulton Armory uppers, both LR-308's, with excellent results. The Fulton might not count as it was very even to start, more confirmed it was square than squared it.

 

My upper will be Fulton, as well, so that's great to know!

As an aside, I recently lapped 2 Fulton AR-15 uppers. One was perfect from the start -- perfectly round shiny spot after "touching" it with the lapping tool, just as a guide.

The second one, on the other hand, was a beast...

Share this post


Link to post
Share on other sites
Just now, COBrien said:

The second one, on the other hand, was a beast...

Two DPMS AR-15 uppers pretty much ruined my AR-15 lapping tool they needed so much off. These tools are an expendable thing unless you get a machinist to reface them after wearing a groove and they would most likely charge as much or more than a new tool.

Share this post


Link to post
Share on other sites
13 minutes ago, jtallen83 said:

These tools are an expendable thing unless you get a machinist to reface them after wearing a groove and they would most likely charge as much or more than a new tool.

I know a machinist who would do it for you free if you paid the shipping cost.

Share this post


Link to post
Share on other sites
58 minutes ago, Matt.Cross said:

I know a machinist who would do it for you free if you paid the shipping cost.

Bookmarking this post... 🤣

Share this post


Link to post
Share on other sites
1 hour ago, Matt.Cross said:

I know a machinist who would do it for you free if you paid the shipping cost.

If I hear of some of those carrier weights becoming available I might drop it in the mail so the shipping can be cost averaged a bit, suckers are heavy! :thumbup:

Share this post


Link to post
Share on other sites
12 minutes ago, jtallen83 said:

If I hear of some of those carrier weights becoming available I might drop it in the mail so the shipping can be cost averaged a bit, suckers are heavy! :thumbup:

I can make you a one-off any time.

Share this post


Link to post
Share on other sites
1 minute ago, Matt.Cross said:

I can make you a one-off any time.

Can you do both large and small frame versions? I may just take you up on that come late summer/early fall when I will be around home a bit.

Share this post


Link to post
Share on other sites
16 minutes ago, jtallen83 said:

Can you do both large and small frame versions? I may just take you up on that come late summer/early fall when I will be around home a bit.

Sure can, as far as I know there's no difference in the specs, but that's a trivial problem if any.

Share this post


Link to post
Share on other sites
39 minutes ago, jtallen83 said:

If I hear of some of those carrier weights becoming available I might drop it in the mail so the shipping can be cost averaged a bit, suckers are heavy! :thumbup:

 

22 minutes ago, jtallen83 said:

Can you do both large and small frame versions?

They're identical - same part, dimensions don't change.  I have one in a 16" 5.56 precision gun, and one in a LR-308.  :thumbup:

Share this post


Link to post
Share on other sites
26 minutes ago, Matt.Cross said:

Sure can, as far as I know there's no difference in the specs, but that's a trivial problem if any.

 

20 minutes ago, 98Z5V said:

 

They're identical - same part, dimensions don't change.  I have one in a 16" 5.56 precision gun, and one in a LR-308.  :thumbup:

Can they be made in different weights? 

Share this post


Link to post
Share on other sites
1 minute ago, jtallen83 said:

 

Can they be made in different weights? 

Long answer short, yes. It's basically a housing that carries different weight inserts. You can use the housing by itself, or in conjunction with inserts of various types and weights.

Share this post


Link to post
Share on other sites

If there's a lot of interest in this, I'll go ahead and make a batch of them. I just need numbers for how many everyone wants.

Share this post


Link to post
Share on other sites
29 minutes ago, jtallen83 said:

 

Can they be made in different weights? 

1.  Housing alone. 

2.  Housing with steel insert.

3.  Housing with Tungsten insert.

3 total possibilities.  :thumbup:

Share this post


Link to post
Share on other sites
1 hour ago, 98Z5V said:

1.  Housing alone. 

2.  Housing with steel insert.

3.  Housing with Tungsten insert.

3 total possibilities.  :thumbup:

Tungsten, Carbide, Steel, Aluminum, Plastic....

The insert possibilities are endless, the housing necessarily needs to be machinable, but there's also many possibilities there.

Share this post


Link to post
Share on other sites

Now, then, we know this will work in DPMS-pattern uppers.

Will it work in Armalite uppers?

I have a buddy who's just bought a complete AR-10 who wants to install a JP handguard on it. While we've got it apart, I'd like to lap the upper for him.

Does anyone have a blueprint and/or measurements for the I.D. of an LR-308 upper vs. an AR-10 upper?

Share this post


Link to post
Share on other sites
2 hours ago, COBrien said:

Now, then, we know this will work in DPMS-pattern uppers.

Will it work in Armalite uppers?

I have a buddy who's just bought a complete AR-10 who wants to install a JP handguard on it. While we've got it apart, I'd like to lap the upper for him.

Does anyone have a blueprint and/or measurements for the I.D. of an LR-308 upper vs. an AR-10 upper?

Blueprint not necessary.  It will work.  I have an AR-10 barrel mounted in a DPMS-based rifle - fits.  It'll work.  :thumbup:

Share this post


Link to post
Share on other sites
1 hour ago, 98Z5V said:

Blueprint not necessary.  It will work.  I have an AR-10 barrel mounted in a DPMS-based rifle - fits.  It'll work.  :thumbup:

'Preciate that, brother!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×