The MIT collegiate team had a match this weekend. One of our shooters was shooting a Hammerli 160, and started getting misfires. We had two spares, one I had just adjusted the trigger on but not touched the breechblock, and one where I just completely disassembled, cleaned & oiled the breechblock. Both of those exhibited the same problem.
We tried CCI and RWS ammo, and both had issues. We switched to Aguila, and things got better, but were less than perfect.
I'm not sure which one he finished up with, but I am baffled as to how three normally reliable pistols could suddenly start misfiring with three different types of ammo. The one I just rebuilt has a new firing pin spring, and it's got plenty of punch. The firing pin looked OK compared with a new one, so I didn't replace it.
Is there any sort of headspace adjustment on these things? Any other ideas? We have a couple more flavors of ammo we can try, but this is really puzzling.
One thing I did notice is that someone has swapped the breechblocks around between at least two of the pistols. That could affect the headspace for sure, but if they aren't identical, I would think one would be short.
Any ideas or suggestions are welcome.
Thanks!
Light Hits with THREE Hammerli 160's
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tight chambers
The chambers in the 150s and 160s are very tight. In fact in my 150 it's too painful to my fingers to use CCI because of the pressure required to chamber a round. Is it possible the shooter(s?) in this instance was simply not pushing the rounds all the way into the chamber (i.e. not closing the lever completely into battery), and the light hits were caused by the rounds moving as the firing pin hit them? Just a thought.
FredB
FredB
Re: tight chambers
Yes, it is the same with my 160. But the RWS should workFredB wrote:The chambers in the 150s and 160s are very tight. In fact in my 150 it's too painful to my fingers to use CCI because of the pressure required to chamber a round. Is it possible the shooter(s?) in this instance was simply not pushing the rounds all the way into the chamber (i.e. not closing the lever completely into battery), and the light hits were caused by the rounds moving as the firing pin hit them? Just a thought.
FredB
YOU SHOULD NEVER FIRE A 160 WITH THE BREECH NOT COMPLETELY COSED AS THERE IS A MAJOR RISK TO BREAK THE FIRING PIN or its ARMING LEVER.
On the 160, the firing pin is a cylinder with a kind of side pin on its left side. The breech opening and cocking lever uses this side pin to arm the firing pin. If you fire the pistol with the breech partially open, this arming pin will hit the cocking lever and either this pin or the firing pin cylinder may break. The risk is higher if the breech is almost closed because then the firing pin will be at its higest speed when its side pin hit the cocking lever. When the firing pin is broken and you fire the pistol, it makes a soft sound and sometime a soft hit on the .22lr rim (when the cylinder is broken in two pieces, the rear piece is armed, sometimes the rear part hitting the front part that carry the actual firing pin is enough to mark the .22lr rim or even fire the shot).
Below a drawing of the firing pin:
And a drawing when it is broken in two pieces:
You also should never store the pistol with its firing pin armed to avoid to leave the firing pin spring compressed for a long time.
I only had time to deal with one of the pistols today, so I took apart the one that he had been shooting successfully up until this weekend.
Fortunately, the problem was pretty obvious. The pistol was in need of a cleaning, and the "catch" at the back of the breech block wasn't releasing the "discharge latch". I took the breechblock apart, cleaned & oiled everything, and it appeared to be fine. The shooter went off the practice & did fine for a while, and then suddenly started getting "misfires" again.
I think the problem is one we've seen before. Once they settle into shooting, the students get a little sloppy about making sure they pull the cocking lever ALL the way against the stop, and the firing pin never latches back. With the firing pin protruding from the front of the breechblock, it puts a small scratch on the case, which looks a bit like a light hit.
We were running out of time, but I think that fixed the problem. There is a good chance that was what was happening with the other two pistols he tried as well. Until I have a chance to check them over, that's my story & I'm sticking to it...
The extra good news is that two of the team members announced their engagement today!
Fortunately, the problem was pretty obvious. The pistol was in need of a cleaning, and the "catch" at the back of the breech block wasn't releasing the "discharge latch". I took the breechblock apart, cleaned & oiled everything, and it appeared to be fine. The shooter went off the practice & did fine for a while, and then suddenly started getting "misfires" again.
I think the problem is one we've seen before. Once they settle into shooting, the students get a little sloppy about making sure they pull the cocking lever ALL the way against the stop, and the firing pin never latches back. With the firing pin protruding from the front of the breechblock, it puts a small scratch on the case, which looks a bit like a light hit.
We were running out of time, but I think that fixed the problem. There is a good chance that was what was happening with the other two pistols he tried as well. Until I have a chance to check them over, that's my story & I'm sticking to it...
The extra good news is that two of the team members announced their engagement today!