Posts: 69
Threads: 6
Joined: Jun 2017
09-17-2017, 06:03 PM
(This post was last modified: 09-17-2017, 06:13 PM by derek45.)
Comparing with standard 5.56 parts....
Looks like the firing pin is off by .010" also to make up for it.
Looks like it should work.
(.....until I need a new firing pin. )
![[Image: 16ZoOYv.jpg]](https://i.imgur.com/16ZoOYv.jpg)
![[Image: OFfXHVy.jpg]](https://i.imgur.com/OFfXHVy.jpg)
![[Image: PbbqDQQ.jpg]](https://i.imgur.com/PbbqDQQ.jpg)
NRA LIFE
USPSA-IPSC
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."
-Jeff Cooper
Posts: 678
Threads: 7
Joined: Apr 2017
I had one sitting on the bench thats 2.815 or 2.816.
Posts: 69
Threads: 6
Joined: Jun 2017
Lastrites Wrote:I had one sitting on the bench thats 2.815 or 2.816.
JP or Brownells ?
NRA LIFE
USPSA-IPSC
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."
-Jeff Cooper
Posts: 42
Threads: 10
Joined: Sep 2017
I wonder if it's a rebranded Tool Craft Bolt...
That's the one I bought for my first Grendel upper and was impressed.
Posts: 69
Threads: 6
Joined: Jun 2017
AP Smizzlers Wrote:I wonder if it's a rebranded Tool Craft Bolt...
That's the one I bought for my first Grendel upper and was impressed.
I wondered before I bought it
I emailed brownells Friday night, asking if they had spare extractors for it.
We'll see what they
I'll LOL if they prefer me to toolcraft
NRA LIFE
USPSA-IPSC
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."
-Jeff Cooper
Posts: 6,206
Threads: 50
Joined: Mar 2011
Derek45, I wasn't trying to alarm you but since there was so little information on the Brownell's 6.5 Grendel BCG I thought I'd mention it. I know there have been a couple of manufactures who distributed bolts with 2.80 length bolts with standard firing pins which contributed to pierced primers. The solution was to modify the firing pin protrusion by .01. The only downside with the short bolt length is the non standard firing pin. I would have been surprised if Brownell's had not investigated the 6.5 Grendel bolt/carrier before brininging it to market.
With the way tolerances stack this may not be an issue in every barrel BCG combination.
Posts: 69
Threads: 6
Joined: Jun 2017
I think as long as I remember that it takes a non USGI length firing pin, it should be OK
Do you agree ?
I was a bit alarmed when I first read your reply, groggy from a long shift Saturday, and sleeping in Sunday.
. . but after some good coffee, I started looking and measuring and things started to make sense LOL
I have to take my wife to the hospital Monday afternoon, but afterward, if there's time, I plan I test firing it ( with the brownells bolt/carrier and new FAXON 16" Gunner )
I'll save brass, and report back afterward.
NRA LIFE
USPSA-IPSC
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."
-Jeff Cooper
Posts: 6,206
Threads: 50
Joined: Mar 2011
With the firing pin supplied with the Brownell's bolt I think your BCG is gtg. Unfortunately a couple of times standard length firing pins were supplied and a couple manufactures got caught napping. It's a simple fix but is disconcerting on a new build to get pierced primers.
The only issue I foresee is if someone buys a Brownell's bolt and it eventually fails. The owner then buys a .281 length 6.5 Grendel bolt and then he encounters light firing pin strikes when he tries to use his Brownell's firing pin. Had I not been on the forum for several years I would have wondered why things weren't working.
At least with the length issue of 6.5 Grendel bolt being discussed on this forum members are enlightened on some of the individual characteristics of going to a non standard caliber in the AR-15. Had I been doing the specifications on a new product for Brownell's I'd probably spec a .281 bolt and standard firing pin. Could be Brownell's had a couple of vendors price BCG and Brownell's wasn't aware of the .280 and non standard firing pin compared to .281 and standard firing pin.
Posts: 8,507
Threads: 241
Joined: Sep 2014
One of the things Bill A. did to make Grendel as compatible as possible was spec the longer 2.810" bolt that would work with standard firing pins, so people wouldn't have to try to find another non-spec firing pin. It was one of the most overlooked dimensions on bolts in the after market.
Extractor pocket depth and pin location is different too so it will snap over the rim without impinging on the barrel extension teeth.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
Posts: 69
Threads: 6
Joined: Jun 2017
brownells bolt ran fine tonight. primers look fine.
no problems
Life is Good
NRA LIFE
USPSA-IPSC
"The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles."
-Jeff Cooper
Posts: 164
Threads: 23
Joined: Dec 2016
derek45 Wrote:brownells bolt ran fine tonight. primers look fine.
no problems
Life is Good
It should be fine with the shorter FP. I know Odin Works does the same thing. Evidently LaRue does too. Just measured the bolt & FP from my LaRue 6.5 Grendel upper. Bolt is 2.800 and FP is 3.270.
Cliff
USN Ret., FPD Ret.
Dues Vult
Posts: 1,198
Threads: 52
Joined: Jan 2016
09-20-2017, 03:19 AM
(This post was last modified: 09-20-2017, 03:43 AM by Kilco.)
cb4017 Wrote:It should be fine with the shorter FP. I know Odin Works does the same thing. Evidently LaRue does too. Just measured the bolt & FP from my LaRue 6.5 Grendel upper. Bolt is 2.800 and FP is 3.270.
Measured my Odin Works bolt/firing pin and you are absolutely correct!! Rather disconcerting...
So if I understand correctly, if I want a replacement firing pin I need one specifically for 3.370?
Also how does the 2.800 bolt effect headspace? Can I only use bolts that measure 2.800 or would a 2.810 bolt with standard firing pin work?
Posts: 164
Threads: 23
Joined: Dec 2016
Kilco Wrote:The bolt that came with my Odin Works 16" kit is 2.810 long and uses a standard firing pin. I've interchanged it with standard 5.56 bolts.
Hmm, the bolt that came with my Odin Works 20" is 2.800 with a shorter FP. Guess they do it both ways.
Cliff
USN Ret., FPD Ret.
Dues Vult
Posts: 1,198
Threads: 52
Joined: Jan 2016
09-20-2017, 03:44 AM
(This post was last modified: 09-20-2017, 03:48 AM by Kilco.)
cb4017 Wrote:Hmm, the bolt that came with my Odin Works 20" is 2.800 with a shorter FP. Guess they do it both ways.
I measured again after reading your post and you were correct.
The extra pin I have is for an AA bolt that came with my Shilen barrel.
I edited my post and I have a couple questions regarding these 2.800 bolts and shorter firing pins.
Posts: 164
Threads: 23
Joined: Dec 2016
Kilco Wrote:Measured my Odin Works bolt/firing pin and you are absolutely correct!! Rather disconcerting...
So if I understand correctly, if I want a replacement firing pin I need one specifically for 3.370?
Also how does the 2.800 bolt effect headspace? Can I only use bolts that measure 2.800 or would a 2.810 bolt with standard firing pin work?
Correct. You would need the shorter FP in a 2.800" bolt. You may pierce primers with a standard length FP.
Either bolt would work as long as the appropriate FP is used. Should make no difference in headspace as long as the bolt has the correct .136" recess.
Truthfully it is probably not something I would get too worried about. In almost 40 years of shooting AR pattern guns, including my M-16, I have never broke or worn out a FP.
Cliff
USN Ret., FPD Ret.
Dues Vult
Posts: 6,206
Threads: 50
Joined: Mar 2011
The only real down side is if a bolt fails you need to make sure you buy the same length bolt. If I broke a bolt on my LaRue I’m sure I’d get another bolt from LaRue. If it was a Franken build with a wide variety of parts from numerous sources it’s going to happen where someone is going to use the 2.81 bolt with a short firing pin or vice versa.
As much as Bill A tried to get standardization this is another example where the 6.5 Grendel has it’s little nuances. If a person only shoots 20 rounds a year with their hunting 6.5 Grendel they’ll probably never encounter a problem.
Posts: 1,198
Threads: 52
Joined: Jan 2016
VASCAR2 Wrote:The only real down side is if a bolt fails you need to make sure you buy the same length bolt. If I broke a bolt on my LaRue Im sure Id get another bolt from LaRue. If it was a Franken build with a wide variety of parts from numerous sources its going to happen where someone is going to use the 2.81 bolt with a short firing pin or vice versa.
As much as Bill A tried to get standardization this is another example where the 6.5 Grendel has its little nuances. If a person only shoots 20 rounds a year with their hunting 6.5 Grendel theyll probably never encounter a problem.
If my setup came with a 2.800 bolt/pin I could always swap to the 2.810 bolt and standard firing pin though, right?
Posts: 678
Threads: 7
Joined: Apr 2017
Kilco Wrote:If my setup came with a 2.800 bolt/pin I could always swap to the 2.810 bolt and standard firing pin though, right?
Yep, also a std firing pin can easily be reduced that small .010 amount. Chuck it in a drill and spin it on some sand paper or fine file.
Posts: 604
Threads: 45
Joined: Nov 2016
09-21-2017, 02:32 AM
(This post was last modified: 09-21-2017, 02:34 AM by The Profit Joseph Sith.)
Lastrites Wrote:Yep, also a std firing pin can easily be reduced that small .010 amount. Chuck it in a drill and spin it on some sand paper or fine file.
They are usually chrome lined per mil spec I believe. So I definitely wouldn't do that to the pin side. It would probably Stark to flake off or delaminate over time. Especially if rust starts. I wouldn't recommend it at all. I'd definitely avoid this whole debacle. Im sure I'd forget. Heck I remember reading this before about the longer bolts and already forgot.. I try and K.I.S.S. as much as possible.
Has anyone measured the Lehigh bolts yet? One of the reason I pick the parts I do is for main stream compatibility. What can I say, standards are great things!
The one great thing about bronwells though is they have that 100% lifetime return policy. And so much of their stuff is made in the US of A. Love them for that.
Posts: 604
Threads: 45
Joined: Nov 2016
Just received my six BCG's from AIM Surplus. They look great. Tolerances are all within .002" at worst. I would recommend them. They are the 5.56 basic nitride ones. They ARE NOT HP tested which is something I was specifically looking for. Full mass carrier good for potential modifying in the future, I might try my hand at drilling and tapping for side charger bolt handles.
|
