March 5th, 2019

When ARs Fail — Busted Bolt Incident

AR15 AR-15 Bolt failure Broken AR Bolt Police Department

Our friend Dennis Santiago was recently conducting training for a Southern California Police Department. During a training session one of the unit’s AR15s stopped functioning. The problem — the bolt in the AR rifle broke in half. Dennis states: “They ran the gun dry, broke for lunch, shot it again. They don’t like that. I personally like to flood the bolt wet with lube on training days. It prevents stuff like this. Given that, it’s a simple remove-and-replace fix.”

AR15 AR-15 Bolt failure Broken AR Bolt Police Department

Here are some of the more interesting comments about this parts failure — an AR bolt that literally sheared in half:

“If I was a betting man [the steel] wasn’t made by Carpenter Steel. They are one of the few companies that use the correct [milspec-steel, C-158] called out on the drawing which they coincidentally developed. Most of the other companies that make [AR Bolts] use different steel with the same heat treat specification as what is called out which gives them the potential of being a little on the brittle side at the upper end of the tolerance. When it comes to the AR platform, bolts are probably the only part of the entire gun where I must admit to being a little bit of a brand snob.” David O’N.

[Editor’s Note: Actually Carpenter Steel does not make AR bolts. They are a steel supplier, and yes Carpenter did develop the original C-158 steel for AR bolts. Here is a contrary view, claiming that AISI 9310 Steel is actually stronger than milspec Carpenter C-158: 9310 Steel for AR Bolts.]

“Dry bolt and carrier shouldn’t cause that. Looks like a big pressure spike. What kind of ammo…?” Guy G.
Reply from Dennis: “55gr factory ammo.Piles of it.

“Is that the new two-piece bolt everyone’s been talking about LOL?” — Darren R.

“Let me guess…the PD called you in cause they didn’t know why it stopped going ‘pew pew’?” — Jim O.
Reply from Dennis: “I was there today for qualifications. It broke during the rifle phase. Simple enough to fish the bolt parts out of the action. The training didn’t miss a beat. I have an armory full of the things.”

Permalink Gunsmithing, Tactical, Tech Tip 14 Comments »
March 5th, 2019

Complete 6.5×47 Benchrest Rifle Build — Start to Finish on Video

S&S Precision 6.5x47This video, produced for the folks at S&S Precision in Argyle, Texas, shows a full custom 6.5×47 bench rifle being crafted from start to finish. It is a fantastic video, one of the best precision rifles video you’ll find on YouTube. It shows every aspect of the job — action bedding, chambering, barrel-fitting, muzzle crowning, and stock finishing.

You’ll be amazed at the paint job on this rig — complete with flames and four playing cards: the 6, 5, 4, and 7 of spades. Everyone should take the time to watch this 13-minute video from start to finish, particularly if you are interested in stock painting or precision gunsmithing. And the video has a “happy ending”. This custom 6.5×47 proves to be a real tack-driver, shooting a 0.274″ three-shot group at 400 yards to win “small group” in its first fun match. NOTE: If you have a fast internet connection, we recommend you watch this video in 720p HD.

Permalink - Videos, Gunsmithing 6 Comments »