right right right right
bottom bottom bottom bottom right

AR Hunting, Preparedness and Survival
Sign up Calendar Latest Topics
 
 
 


Reply
  Author   Comment  
arnie

jager
Registered:
Posts: 87
Reply with quote  #1 
On my new 6.5 Grendel build ,every thing functions fine except the bolt doesn't lock back most of the time on the last shot. Locks back fine by hand. Load is the same that functions fine in my other two Grendels  .Tried stretching the mag spring and different mags and still doesn't lock back .Im guessing removing some weight from the buffer might cure this ,or removing a coil or two from the buffer spring ,might cure this ??  
0
Borrego Bob

Avatar / Picture

Moderator
Registered:
Posts: 3,336
Reply with quote  #2 
Wonder if it's under gased check your gas block Allignment.
__________________
“What’s the secret of success? Right decisions. How do you make right decisions? Experience. How do you get experience? Wrong decisions.” – John Wayne

0
arnie

jager
Registered:
Posts: 87
Reply with quote  #3 
The gas block looks ok and the hole in it is about twice as big as the one in the barrel . I weighed the buffer today and its 4.55 ounces which some one shows as an H2 .I took one weight out of it and will try it Saturday .I might need to get an H which is 3.8 ounces .
0
Tedward

Guide
Registered:
Posts: 506
Reply with quote  #4 
Why would you even use any H Buffers? All of mine cycle fine with a regular buffer. I ordered H and H2 buffers for the collapasable stocks when used on 12.7x42 uppers with Beowulf Ammo and they help the cycling for them in that application. The H seems to do just fine but the Rifle Length uses a heavier buffer than both of those and cycles fine for the Grendel and Beowulf.

I think the differance in weight with the combination of spring length has the effect of different cycling. Best success I found if your going to use the spring and buffer is using an A2 Rifle buffer tube set up. Works good for both calibers.

Also I use the JP Silent Capture buffers and they work with either buffer tube, same spring rate and weight so it functions in both tubes the same.

__________________
http://www.performance-firearms.com
0
arnie

jager
Registered:
Posts: 87
Reply with quote  #5 
I bought the stock as a set with the stock ,tube ,spring and buffer . This is a carbine sliding  stock .I guess they gave me the wrong buffer . The buffer is probably a quality one as it has that real slick black finish on it , but is too heavy as is . I have held a carrier with this same finish ,feels like plastic . Im going to try a lighter buffer first as a carbine is supposed to use one about 1 and 1/2 ounces lighter .
0
arnie

jager
Registered:
Posts: 87
Reply with quote  #6 
ar grendel 003.JPG  ar grendel 002.JPG  ar grendel 007.JPG  ar grendel 006.JPG 
0
arnie

jager
Registered:
Posts: 87
Reply with quote  #7 
The tape on the rear slot is with the bolt locked back and the one with a hand shows how far it can come back .When I fire it ,the tape is undisturbed .I am also going to fire it with out the handle on the bolt so that might lighten things up . Here is the spring and buffer .ar grendel 004.JPG
0
Borrego Bob

Avatar / Picture

Moderator
Registered:
Posts: 3,336
Reply with quote  #8 
80% lower project?
__________________
“What’s the secret of success? Right decisions. How do you make right decisions? Experience. How do you get experience? Wrong decisions.” – John Wayne

0
arnie

jager
Registered:
Posts: 87
Reply with quote  #9 
Yes an 80% from Hellfire .They really look neat in the white as they look jeweled but are so smooth I though it had a clear coating on it but it doesn't .I bought a bead blaster from Harbor Freight and blasted a few and painted them with Brownel's  Aluma-hyde .  I made the side charger out of a smooth side receiver and milled and drilled the carrier with  solid carbide tools .
0
45r

Guide
Registered:
Posts: 102
Reply with quote  #10 
What barrel and gas length.
You can drill the port out a little and use an adjustable gas block if needed.

__________________
KDK
0
arnie

jager
Registered:
Posts: 87
Reply with quote  #11 
Its a 20 inch barrel and a rifle length gas tube .I lightened the buffer 1/2 ounce and it locks back all the time with Hornady factory ammo(123 a max) and almost all the time with my reloads so I am going to lighten the buffer another 1/2 ounce .
0
Tedward

Guide
Registered:
Posts: 506
Reply with quote  #12 
Arnie, I make the side chargers (left charge right eject) but use a custom heavy carrier. Make sure when the bolt carrier is pulled all the way back (remove the charging handle) look in that location and make sure the gas key is about 1/16" from the lower. You don't want it to hit the lower but the bolt will actually cycle within an 1/8" of the gas key hitting the lower. If not you might not be getting the carrier to cycle far enough backward. It has to go past the lock position then come forward to lock. Different loads will cycle further if there hot and you don't want a bump on the charge handle.

If it doesn't cycle that far back, do what I did on my first go around, mill the slot back till the gas key almost hits the lower.

As for weight, I use a heavy carrier, more so than my JP Full Mass. I don't think its a weight of the carrier. and for buffer, I use a light buffer in carbine, only H2 when shooting Beowulf ammo out of a 12.7x42 Satern .50 Cal.

Sounds like its actually just the weight of the buffer.

You'll get it shortly, getting closer..

__________________
http://www.performance-firearms.com
0
arnie

jager
Registered:
Posts: 87
Reply with quote  #13 
Tedward , I will test it Tuesday and also test the PPU brass .I think the brass is too soft in the web area and is swelling enough to make it look like a belted magnum .Same load I use in Lapua and Hornady cases in my other two Grendels .
0
arnie

jager
Registered:
Posts: 87
Reply with quote  #14 
OK ,tested today and the bolt will now lock back with the Hornady factory load and the loads fired in the Lapua cases but not in cases fired in PPU or Hornady cases even though the loads in all my hand loads were the same .So now I am using a buffer of 3.75 ounces and will get one that is 2.9 ounces . I really wonder why Lapua cases hand loaded worked and not the others ? Strange
0
arnie

jager
Registered:
Posts: 87
Reply with quote  #15 
I pulled the gas block off yesterday and it shows it was centered perfectly .I then ran a .063 drill bit in the vent hole and the vent was full of crap .Im guessing when it was painted ,ceracoated or what ever ,some got into that hole or it was never drilled properly as I could feel the bit hit something before it broke through . I opened the vent to .104 and it is functioning real good now with all loads .
0
Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.