Seems there has been history of Grendels breaking bolts: http://www.msrhunt.com/post/grendel-...0032?&trail=15
What bolt lugs? Who needs those?
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The Model 1 gun show sales 7.62x39 bolts would break as a standard feature.
Grendel bolts don't have a habit of breaking. I don't know who did the metallurgy on this one, but they failed big time.
Only bolts I've ever seen break are 5.56 bolts.
Keep in mind I'm not talking about personal anecdotes limited to my guns, but years of seeing people bring Grendels to 2-3 day long courses where we shoot at least 125 rounds per day or more, including cold weather conditions.
MSRhunt is a joke of website BTW. When you have someone that knows just enough information to get themselves into trouble with reloading then decide to start a forum, and that forum attracts everyone that has some bone to pick with 6.5 Grendel, what could go wrong?
MSRhunt was forum member Xcountryrider, banned for multiple CoC violations after organizing a group buy of Liberty barrels that had short throats that were blowing primers on many of the barrels. We advised people that were having problems to stop shooting and contact the manufacturer to correct the issue. Xcountryrider told those forum members to "ignore the haters" and keep on shooting.
Constructor was banned here at least 4 times, and banned from AR15.com 3 or 4 times for CoC violations including posting customer name/address/phone number to punish the customer, then trying to come back as a retread. He has some personal beef with Bill A. I could never understand.
If someone claims there is a history of Grendel bolts breaking, consider the source.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
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I've broken two grendel bolts, and both broke on the same day. The second bolt failed on the first shot. I have since reconsidered my opinions on how much pressure is too much pressure and haven't had another failure in over 5,000 rounds and counting.
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Originally posted by rwh View PostI've broken two grendel bolts, and both broke on the same day. The second bolt failed on the first shot. I have since reconsidered my opinions on how much pressure is too much pressure and haven't had another failure in over 5,000 rounds and counting.When you clean the vacuum cleaner you become the vacuum cleaner.
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Also, when someone tells you the wall thickness of 6.5 Grendel bolts is too thin and will break, have them call up FN and tell them to stop making the SCAR-17 bolts as well.
7.62 NATO can run up to 62,000psi chamber pressure BTW. If the metallurgy is done right, the bolts will be fine. If done wrong, then no matter what the cartridge is, they will have problems.
Last edited by LRRPF52; 09-18-2017, 11:25 PM.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
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I'm no metallurgist but the bolt's fracture surfaces don't look that crystalline to me, they look like MIM or some kind of cast metal... crystalline breaks I've seen have very sharp clear and angular surfaces, these look sort of roundish down at the magnifying-glass level."Down the floor, out the door, Go Brandon Go!!!!!"
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Originally posted by Difranco View PostOnly to the original purchaser. No order number, no return. Just got off the phone with them.
it specifically mentioned passing on to family members, no mention of order number.
send them that linkjust some targets for printing
https://drive.google.com/drive/folde...xQ?usp=sharing
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just some targets for printing
https://drive.google.com/drive/folde...xQ?usp=sharing
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Not to worry. We're taking care of this and making the OP whole.
The last time I saw pics of bolts like this was post-Sandy Hook when shops were letting things fly out the door so quickly, that corners were being cut. Notice the extractor still intact and spent cases look fine. This is another clear example of a failure in the metallurgy process.
These are all 5.56 bolts:
And an M14 bolt just for good measure.
No matter the design, if you screw the heat treating or metallurgy up, expect the part to fail. This is why testing is so important, and not High Pressure Testing, which only weakens the bolt.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
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I'm guessing you have not ordered from Brownells, because if you had you would know this not to be the case at all. I don't know of any company selling firearm parts that will warranty them for life other than Brownells. They are most definitely a stand up company!
I really hate to see anyone slander such a reputable company. The OP is being taken care of, that's all that matters.
Originally posted by mdram View Postthen that add lied
it specifically mentioned passing on to family members, no mention of order number.
send them that link
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Huh, I learned something today! I had no idea on the different bolt lengths. When I built mine, I bought the bolt from Black Rifle Arms (from the description it sure reads like a Lehigh bolt!). I went down & measured & it's 2.81:
IMG_3360.JPG
IMO that's one of those things that should be a standard! Were/ are the Lehigh group buy bolts 2.81?? For folks that want a spare firing pin, you could get a stainless pin from a reputable manufacturer; I wouldn't want to shorten a HC pin either... That's too bad the Toolcraft bolts are 2.80. Though I guess stocking a few extra firing pins, it's not a big deal.
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Originally posted by Difranco View PostHere are pics of the barrel, extension. The 6 O'clock lug has been topped off, I suspect this occurred when the bolt rotated and the bolt lugs falling off. That shot / recoil felt totally normal, case ejected normally, the only reason I new something was up was because it failed to feed. Brass was from Hornady factory ammo, no flattened primers or anything indicating an over pressure (no cratered primer, etc.)
Do you have a picture of the bolt pin that secures the bolt to the bolt carrier? Additionally, it would be interested to take the bolt to a machine shop and have any part of the bolt tested for Rockwell hardness
Do you have the brass that was the result of this bolt sheer? If so, a picture of that would also be helpful.Last edited by Texas; 09-22-2017, 05:04 AM.
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