• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

AR15 Rebuild with pics

So last year I wore out a cheap gas block, it dang near just gummed up, locked up, and was spewing gas from under the block, I started having bad ejection issues and jams left and right...

I bought an SLR adjustable gas block, low and behold it wouldnt fit in the handguard. So I took apart the whole AR, cleaned everything really well, then we moved.

The AR sat around for the last 8 months in pieces. During this time I was researching everything AR and getting back up to date on quality parts, learned how to true up upper receivers, planned on doing that, lots of little ins and outs tricks.

I found one handguard that MIGHT fit with this bull barrel and .936 gas block. When I found this handguard, I found it went with an upper receiver and thats all it would fit. "Shit, now I gotta buy a new upper receiver too, my wifes going to kill me."

Billet vs forged? Whats that? Back to more learning I went. Quickest way to explain it, billet is CNCed out of a block of aluminum to much better tolerances, forged is pressed/stamped/molded into shape and has looser tolerances.

Ok so I thought, we will upgrade the upper receiver too while Im at it, tighten things up spec wise, its my only choice anyways...

I got it all delivered throughout this last week, and finally was able to put it together this morning. Everything came together and low and behold it all fit and worked out!!! I was so worried about the gas block and handguard, they clear and free float, BARLEY!!

The seekins IRMT-3 V3 upper receiver/match handguard was exactly what I needed. The weaked point on an AR upper is the barrel tennon part of the Upper. Seekins came out with this new innovation of a big strong thick barrel tennon. The barrel goes in, and the barrel nut threads into the tennon vs threading on the outside. This takes all the weight of the heavy barrel and supports it much much better while making it truely free floating. The handguard slips on OVER the tennon never contacting the barrel nut, or barrel. This is a much higher quality set up vs the standard configuration. With the standard configuration and stress on the handguard effects and stresses the barrel and receiver, causing receiver flex. (ESPECIALLY WITH THE BARREL I HAVE).

See video below as explained by seekins precision:


New build/upgrade is as follows:

6.5 GRENDEL
  • Ergo palm swell grip
  • Magpul PRS stock
  • Geisselie single stage trigger at 5oz
  • Stag forged lower
  • BOB SLED single shot mag
  • JP silent capture H2 buffer
  • Phase 5 right handed bolt release
  • Extended charging handle
  • Les baer bolt carrier and parts
  • Les baer bolt
  • Triggershim receiver pin shims
  • Triggertech upper "U" shaped cnc spacer/shim. (These two different shims take all the play/gap out of the upper and lower fit, there is no wobble, it is TIGHT fitting, doesnt move, no play).
  • Seekins irmt v3 precision upper receiver
  • Seekins SP3R 15 inch (flat bottom, flat sides, triangle shaped hand guard makes for monolithic rail look.)
  • Seekins 5 slot accessory rail with mounted joypod bipod.
  • Saturn custom built cut rifle barrel 8.725 twist at 24 inches, .960ish at barrel nut, .936 gas block, down to .920 at muzzle, threaded 5/8x24 tpi.
  • American rifle company 1 piece 30 moa scope rail and rings, intigrated bubble level
  • Sightron S-III 5-25 mil/mil FFP
This barrel has shot 3 inch 5 shot groups perfect waterline at 750 yards, hopefully it will be a bit more consistant now. Only thing I got left is getting a seekins billet lower, and getting a cerakote job done, but, cant afford those two things right now...

20190103_123844.jpg
20190103_123828.jpg
20190103_123757.jpg
20190103_123658.jpg
20190103_115201.jpg
 
Last edited:
Nice, very nice. You sound like me. I recently bought my first AR ever. I did not have the slightest idea where to look for aftermarket parts or where! I used one in Vietnam for a while but, it wasn't like the ones available now. Asked a lot of questions and finally got her built. Now, just find time to shoot it.
 
How did you get a 5oz trigger from Geizelle? I checked their sight and they don't seem to have one listed.

I tinkered with it alot... im not sure exactly which one it is anymore. I know its the one he makes that goes the lightest... it may be a 2 stage now that I think of it, I think I basically got rid of the first stage, cleaned up over travel, then have the second stage very very light. Took a bit of tinkering. But its just like a jewell now.. i did it years ago... triggers about 7 years old.
 
So last year I wore out a cheap gas block, it dang near just gummed up, locked up, and was spewing gas from under the block, I started having bad ejection issues and jams left and right...

I bought an SLR adjustable gas block, low and behold it wouldnt fit in the handguard. So I took apart the whole AR, cleaned everything really well, then we moved.

The AR sat around for the last 8 months in pieces. During this time I was researching everything AR and getting back up to date on quality parts, learned how to true up upper receivers, planned on doing that, lots of little ins and outs tricks.

I found one handguard that MIGHT fit with this bull barrel and .936 gas block. When I found this handguard, I found it went with an upper receiver and thats all it would fit. "Shit, now I gotta buy a new upper receiver too, my wifes going to kill me."

Billet vs forged? Whats that? Back to more learning I went. Quickest way to explain it, billet is CNCed out of a block of aluminum to much better tolerances, forged is pressed/stamped/molded into shape and has looser tolerances.

Ok so I thought, we will upgrade the upper receiver too while Im at it, tighten things up spec wise, its my only choice anyways...

I got it all delivered throughout this last week, and finally was able to put it together this morning. Everything came together and low and behold it all fit and worked out!!! I was so worried about the gas block and handguard, they clear and free float, BARLEY!!

The seekins IRMT-3 V3 upper receiver/match handguard was exactly what I needed. The weaked point on an AR upper is the barrel tennon part of the Upper. Seekins came out with this new innovation of a big strong thick barrel tennon. The barrel goes in, and the barrel nut threads into the tennon vs threading on the outside. This takes all the weight of the heavy barrel and supports it much much better while making it truely free floating. The handguard slips on OVER the tennon never contacting the barrel nut, or barrel. This is a much higher quality set up vs the standard configuration. With the standard configuration and stress on the handguard effects and stresses the barrel and receiver, causing receiver flex. (ESPECIALLY WITH THE BARREL I HAVE).

See video below as explained by seekins precision:


New build/upgrade is as follows:

6.5 GRENDEL
  • Ergo palm swell grip
  • Magpul PRS stock
  • Geisselie single stage trigger at 5oz
  • Stag forged lower
  • BOB SLED single shot mag
  • JP silent capture H2 buffer
  • Phase 5 right handed bolt release
  • Extended charging handle
  • Les baer bolt carrier and parts
  • Les baer bolt
  • Triggershim receiver pin shims
  • Triggertech upper "U" shaped cnc spacer/shim. (These two different shims take all the play/gap out of the upper and lower fit, there is no wobble, it is TIGHT fitting, doesnt move, no play).
  • Seekins irmt v3 precision upper receiver
  • Seekins SP3R 15 inch (flat bottom, flat sides, triangle shaped hand guard makes for monolithic rail look.)
  • Seekins 5 slot accessory rail with mounted joypod bipod.
  • Saturn custom built cut rifle barrel 8.725 twist at 24 inches, .960ish at barrel nut, .936 gas block, down to .920 at muzzle, threaded 5/8x24 tpi.
  • American rifle company 1 piece 30 moa scope rail and rings, intigrated bubble level
  • Sightron S-III 5-25 mil/mil FFP
This barrel has shot 3 inch 5 shot groups perfect waterline at 750 yards, hopefully it will be a bit more consistant now. Only thing I got left is getting a seekins billet lower, and getting a cerakote job done, but, cant afford those two things right now...

View attachment 1082265
View attachment 1082266
View attachment 1082267
View attachment 1082268
View attachment 1082269
You will freaking love that silent capture buffer. Never done much ar trigger polishing. Let me know where you read up on that. I just bought a timney Calvin elite for my jp, might need to lighten it up a little
 
You will freaking love that silent capture buffer. Never done much ar trigger polishing. Let me know where you read up on that. I just bought a timney Calvin elite for my jp, might need to lighten it up a little


I didnt read anything. Just looked at it and started tinkering.
 
Sniper, I think you need to go back and re test that trigger!!! Simply put, the design does not allow it. You would need springs so light that the hammer would not have enough force to fire the primer. Any one who could would be selling them and making money hand over fist. Just not possible.
 
So last year I wore out a cheap gas block, it dang near just gummed up, locked up, and was spewing gas from under the block, I started having bad ejection issues and jams left and right...

I bought an SLR adjustable gas block, low and behold it wouldnt fit in the handguard. So I took apart the whole AR, cleaned everything really well, then we moved.

The AR sat around for the last 8 months in pieces. During this time I was researching everything AR and getting back up to date on quality parts, learned how to true up upper receivers, planned on doing that, lots of little ins and outs tricks.

I found one handguard that MIGHT fit with this bull barrel and .936 gas block. When I found this handguard, I found it went with an upper receiver and thats all it would fit. "Shit, now I gotta buy a new upper receiver too, my wifes going to kill me."

Billet vs forged? Whats that? Back to more learning I went. Quickest way to explain it, billet is CNCed out of a block of aluminum to much better tolerances, forged is pressed/stamped/molded into shape and has looser tolerances.

Ok so I thought, we will upgrade the upper receiver too while Im at it, tighten things up spec wise, its my only choice anyways...

I got it all delivered throughout this last week, and finally was able to put it together this morning. Everything came together and low and behold it all fit and worked out!!! I was so worried about the gas block and handguard, they clear and free float, BARLEY!!

The seekins IRMT-3 V3 upper receiver/match handguard was exactly what I needed. The weaked point on an AR upper is the barrel tennon part of the Upper. Seekins came out with this new innovation of a big strong thick barrel tennon. The barrel goes in, and the barrel nut threads into the tennon vs threading on the outside. This takes all the weight of the heavy barrel and supports it much much better while making it truely free floating. The handguard slips on OVER the tennon never contacting the barrel nut, or barrel. This is a much higher quality set up vs the standard configuration. With the standard configuration and stress on the handguard effects and stresses the barrel and receiver, causing receiver flex. (ESPECIALLY WITH THE BARREL I HAVE).

See video below as explained by seekins precision:


New build/upgrade is as follows:

6.5 GRENDEL
  • Ergo palm swell grip
  • Magpul PRS stock
  • Geisselie single stage trigger at 5oz
  • Stag forged lower
  • BOB SLED single shot mag
  • JP silent capture H2 buffer
  • Phase 5 right handed bolt release
  • Extended charging handle
  • Les baer bolt carrier and parts
  • Les baer bolt
  • Triggershim receiver pin shims
  • Triggertech upper "U" shaped cnc spacer/shim. (These two different shims take all the play/gap out of the upper and lower fit, there is no wobble, it is TIGHT fitting, doesnt move, no play).
  • Seekins irmt v3 precision upper receiver
  • Seekins SP3R 15 inch (flat bottom, flat sides, triangle shaped hand guard makes for monolithic rail look.)
  • Seekins 5 slot accessory rail with mounted joypod bipod.
  • Saturn custom built cut rifle barrel 8.725 twist at 24 inches, .960ish at barrel nut, .936 gas block, down to .920 at muzzle, threaded 5/8x24 tpi.
  • American rifle company 1 piece 30 moa scope rail and rings, intigrated bubble level
  • Sightron S-III 5-25 mil/mil FFP
This barrel has shot 3 inch 5 shot groups perfect waterline at 750 yards, hopefully it will be a bit more consistant now. Only thing I got left is getting a seekins billet lower, and getting a cerakote job done, but, cant afford those two things right now...

View attachment 1082265
View attachment 1082266
View attachment 1082267
View attachment 1082268
View attachment 1082269
I know this build was awhile back, but I'm wanting to use the same Seekins upper receiver. Does the receiver come with the barrel nut? Seekins has the receiver in stock, but I can't find the nut on their website. Nice build!!
 
As far as I know, barrel nuts are not sold with a bare upper receiver.
White Oak Armament would have them.
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
164,746
Messages
2,183,470
Members
78,500
Latest member
robbsintexas
Back
Top