peppered chrono

[clodbuster]

Out testing some loads out of my SBH  yesterday when the third shot didn't register on the chrono.  When I looked carefully there were 3 tiny holes in the  display window.  My guess is that a 240 gr jacketed hollowpoint from a major manufacturer shed some of said jacket into the plastic window of the display.  The chrono was placed 10-12 feet ahead of the muzzle.  The load was 24 gr of ww 296 and vel. had been registering about 1400 fps.  any thoughts if this senario is reasonable or was it cosmic dust that pinged my chrono?

[corbanzo]

Any chance that dirt got in the barrel?  Were you shooting off of sandbags?  The muzzle blast could blow stuff into it.  I've knocked my chrono off of a couple of shooting benches from blast on larger guns...  I made a little mount so it can drop it just below the front end of the bench so the blast doesnt hit it.  '

Mostly my fault cause usually i chrono at 5-7 feet no matter what I'm shooting...  but with a little mod, it works good.

[clodbuster]

I think everything was right.  The barrel was thoroughly rodded just before going out to my private shooting place.  I rest my hands on 2x8 slabs with a leather bag on top.  Just can't see the muzzle being close enough to blast anything 10 feet and cut a hole in the tough plastic window on the front of a ProChrono unit.   It was the sixth shot of the day over the chrono that did the damage and the third shot from the SBH. Thanks for your thinking about this.

[Graybeard]

Strange things happen. I've fired both revolvers and rifles and felt the sting of jacket material on my face. I've even had them draw blood a few times. How and why I got no clue but it happens.

My best guess in the case of revolvers is that the cylinder and barrel were not quite perfectly aligned at the shot and some parts of the bullet were sheared off as it entered the barrel from the cylinder and in effect bounced back at me. I know I've had this happen with lead bullets from both rimfires and centerfires. I once had a S&W 17 that was super accurate but had a real problem with lead build up around the barrel where some was shaved off as it shot. Many times this one spit lead into my face. Just one more reason to always use shooting glasses.

I had a S&W 29 many long years ago I bought at the shop at the range where I shot. In my first cylinder of ammo from it I got hit in the face at least 2-3 times one bringing a fair bit of blood from my cheek. Needless to say I took it back inside and demanded my money back.

Weird stuff happens all the time. I have no specific explaination to offer on what happened to your chrono but I'm never surprised anymore when things other than a nice whole bullet goes out the end of my barrel.

[Siskiyou]

LEO’s that were in law enforcement in the days of the sixgun should have some memories of the bullet-shaving problem.  I can remember a number of times out on the firing line when the officer's revolver along side me was shaving lead or jacket material.  The shooter in most cases did not realize their weapon was shaving the bullet. 

In my own experience I experience sharp pain and was bleeding out the side of my face.  In fact I was rather PO.

I had been a revolver shooter long before I entered law enforcement.  Most of my shooting was done on my own or with friends and there was normally good spacing between us when shooting.   Normally one would be up front shooting and the second shooter standing back and watching.  I never realized how big of a problem bullet-shaving was until I felt the sting on my face.

I do not know what the exact spacing between law enforcement shooters were on the firing line, but 3 or 4 feet between shooters would not be unreasonable. 

Academy firearms took a real beating firing thousands of rounds, and some of them were bad shavers.  In my case duty weapons we inspected annually.  Timing became an issue with the M19/M66.  I have also seen brand new factory S&W revolvers with the problem.

[jhalcott]

  Perhaps a bit of the jacket left from the previous shot was then carried out and separated from the bullet. I can't see any thing "blown" off the bench doing damage to the chrono screen. I HAVE seen bullets come apart in flight though. I usually set my chrono about 20 feet from the muzzle. I also have a lexan screen in front of my chrono because I shoot a lot of cast gas checked ammo. Lyman checks are NOT crimped on and hornady's occasionally leave the bullet. Did you inspect the bullets for nose damage before you shot them? Also that charge of 296 is a bit high for MY SBH, I get sticky cases at 22.5 and ~1400 fps.!

[Siskiyou]

This topic has me thinking about putting an Anti-Glare screen protector on my Chrony.  I have installed screen protectors on my gps units and it did not take long.  Such a protector might protect the Chrony screen from other mishaps that might damage the screen.  It might protect it from low velocity particles, but would not protect from high velocity debris.

I used a product sold as a PDA screen protector on my gps units.  I purchased it at an office supply store.  It is a very thin adhesive material that is used in shooting glasses.

[Questor]

This is one of the nice things about having a chronograph separate from the sensors. I've shot my sensors twice, but the chronograph was unscathed. The sensors were relatively cheap to replace.

[Siskiyou]

My Chrony has a remote screen and it maybe set up for damage from a revolver with escaping gas from the cylinder gap.  While mine has had a duty tune-up and inspected by gunsmith my shooting buddies guns have never visited a smith.

The remote screen is normaly setting on the bench close to me, but more in line with the cylinder.  Frankly I never thought about that before because it is rare that I shoot a revolver from the bench but it does happen.

[jhalcott]

  shavings from a revolver USUALLY go out to the side. Some times they ricochet Back at the shooter. To hit the chrono they have to curve around the gun and barrel and fly forward. When a gas check comes off the bullet ,it is traveling in the direction of the shot. It loses velocity very quickly and so drops a good bit in the first 10-15 feet. I damaged a few bullets by OVER crimping them. When I shot them at 25 yards at a paper target, there were some small holes that went thru the target around the bullet hole. I got some bullets once that were made from an alloy of zinc/aluminum that is used to coat "tin" plate and prevent rusting. They were incredibly hard and would shatter on firing every now and then.