M305 goes full auto.

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I need some help with regard to a shooting experience I had today.

I went to sight my M305 with Winchester 150 grs soft point factory loads, and had to single load as per range regulations (Quebec province.... yes, I know too......).

At some point I loaded two rounds in mag to speed up things a bit and when I touched it off, both rounds went in full auto mode. Nice I must admit, but not what is expected at this shooting site........... :oops:

Having said that, I also had the same experience with one of my two Garands.

I did not tinker with the trigger group except for some lubrication/grease.

Anyone ever experienced the same thing??


I remember reading something about "milking the trigger" or sort of incomplete trigger pull or too slow could create an unsafe situation with full auto bursts.

tks in advance,
 
Another thing to check would be the bolt and hammer engagement....I have seen a couple bolts that were a little sparse in the area that contacts the raised spur on the hammer...in one particular instance with a well used trigger group where the hammer spur was worn down a bit, this particular bolt (TRW!)/trigger group would function such that when cycling the rearward motion of the bolt would move the hammer back JUST barely enough to engage the disconnector hooks in the trigger group.

I did not notice this when assembling the gun, instead checking for all the usual stuff such as lug engagement and headspace. I put several thousand rounds through the gun, and then one day while doing my daily dry fire practice was wondering why it was a guy would always practice disconnector test when playing with a pistol (as taught in a SIGAcadamy course) but never with a rifle. Imagine my horror as I conducted the drill (drop hammer, hold trigger down while cycling action) and saw the hammer follow the bolt back and forth. It turns out that under recoil the trigger was being relaxed just a bit and the regular sear was what was grabbing the hammer, NOT the disconnector. The rearward motion of the hammer was insufficient with the combination of the older, worn hammer and the slightly shortened spur, thus the hammer following the bolt on the drill.

I consider myself extremely lucky to have experienced this in dry fire practice...were it to happen under live fire conditions several things are in my mind possible. The best case scenario is that nothing would happen, as some have told be that a hammer strike on a bolt that has not rotated completely into battery will not align properly with the firing pin and thus cannot fire. However after careful study I don't necessarily believe this.

Second case scenario is that the gun would go full auto until either the mag is empty or the trigger is released with the sear catching the hammer. Hopefully rounds 4 and 5 (shot off at 30 and 45 degrees vertically to the original point of aim) would land safely many miles away.

Third case scenario would be an out of battery ignition. Lots of hot gas and metal to worry about...shooter is usually ok with possible damage to hands and eyes...people to the side would likely be at significant risk.

While the above scenario is not very likely to be your culprit (soft primer or seized firing pin more likely IMHO), with so many people switching out components in their M305s I thought I would pass the experience on. Can post some pics of the culprit bolt (switched it out with a less worn TRW bolt and problem went away...gun passes disconnector function test no problem) if you guys are interested.

EDITED TO ADD: photographs comparing normal bolt (left) to the hammer-ride-inducing TRW bolt (right)

hammer_spur_bolt_comparison_a.jpg


hammer_spur_bolt_comparison_b.jpg


Take care,

Brobee
 
Strip your bolt, and check the firing-pin channel for debris... Some M305s pierce primers, and the primer metal extrudes into the firing-pin channel under pressure and breaks off. Eventually, enough material will accumulate to interfere with firing-pin movement. I don't think this is the most likely cause of your problem, but it's an easy thing to check...
 
First, doubling is not Full Auto - it's doubling. :D Doubling is usually caused from two stage triggers in which the hammer hooks or sears are not to spec and are allowing the hammer hooks to travel between the two sears without engaging either and/or not engaging the trigger sear when the hammer pops up from the secondary sear when the trigger is released. The hammer and or sear/s need to be replaced. Take it to someone who knows two stage setups and have them evaluate what you need to replace. Usually doubling is the result of someone who at some point in time has filed or ground one of the four engagement hooks of either the hammer and/or sears.
 
Thanks for the explanation and difference between full auto vs. doubling.

I did not have the opportunity to verify the difference since I had loaded two rounds only. :wink:

Having said that I would like to know about someone in Mtl or close by who knows two stage trigger setups please.

Could over lubrication with grease create a dangerous situation too??
I can see that there's a lot in there.....

I also tried the drill suggested by Brobee (see above) e.g. cocking the bolt, pulling the trigger and keeping the trigger back while cycling the op rod again and the hammer does not recock ..... :shock:


enough for today.........
 
I had the same thing happen to me at the range, I loaded 2 rounds in the magazine of my M-305 and began to focus on my target, which was a clay pigeon at 300 yards. I was pulling the trigger slowly when all of a sudden the gun was empty. The guy shooting next to me said that I had found that magic trigger position, because I was pulling the trigger slowly the recoil of the gun caused me to pull the trigger twice, but it felt like I pulled once. At first I thought there was something wrong with the rifle, but I had just bought it and had it checked out and everything was fine. I don't know if this is the problem, it just a suggestion.

Kyrol

P.S I hit the clay pigeon.
 
A useless comment follows but I just gotta say it:

Holy crap, there are ranges that actually allow single loading only???? Are these ranges aware they are happily furthering the anti firearms campaign by attempting to render repeaters into single shots, even if only during practice. :shock: ? This is just sooo wrong, and remarkably stupid. :evil: I'd shoot solely in the bush personally if the club wouldn't change its position after being challenged on the issue. :|
 
I also tried the drill suggested by Brobee (see above) e.g. cocking the bolt, pulling the trigger and keeping the trigger back while cycling the op rod again and the hammer does not recock .....
Click to expand...

Have you changed any components from stock M305? Sometimes a USGI stock can be a bit thicker in the area between the action and the trigger group and this will keep the disconnect from engaging (trigger back, cycle oprod, hammer follows bolt) when the rifle is assembled. It's an easy fix as you just remove a bit of material from under the rear of the trigger group.
If it's stock and it's doing this, send it back for a replacement.
 
Hi Hitzy,

tks for reply and help..... here.

I just did that (USGI stock), light sanding right behind where's the trigger group.

Reassembled cycled 10 times and it cocked back most of the times except a few times when I noticed the racking of the op rod was slightly less forceful.

additional sanding required??

more comments
 
That is some NASTY bolt damage/wear there Broby :shock: . Which brings the questions : Are M-14 type bolts supposed to wear like that ? And if so how did the U.S. military manuals address the problem ? Is there a guage(sp?) or a "standard" out there to inspect bolts determine if it is worn out and should be replaced ? How did the guys in the military (and presumably still do since there are still M-14's in the inventory) replace bolts and fit and headspace them ? (using specialised equipment, and done only at the depot level, I would presume). Seems like that pic would be worthy of a sticky so people could check for that type of thing before it creates a dangerous condition ! :idea:
 
Brobee,

Hi,

I kept investigating my gun failure (doubling) and finally found the issue or problem. as you had justly stated, the hammer portion on top that serves to #### when bolt rides in on its way back was worn just enough to make it fail the disconnectoe test.
I had noticed when stripping gun for the first time that the trigger groupm and hammer and under the bolt were all dry and completely greaseless.........

Although I trust the previous owner about the fact that this rifle had fired less than 50 rounds, I suspect that the lack of lubrication combined with soft metal surface made for fast wearing of this spurred area.
I finally fixed the problem by using one of my M1 Garand SA hammer and when looking side by side at the two parts, it is quite obvious to the eye.

thanks for your advice.

I believe all M305 owners should beware of this potential issue.........

regards,
 
lol i had the EXACT same problem yesterday......
2 shots in a row it was pritty sweet feeling but still.............
and i hit the target with both bullets lol....
i think it had to do with the recoil and stuff.
talk to ya all later
Riley
 
"Doubling"

Hi death-junky,

As per Brobee suggestion, run the drill he's describing and you will be able to determine rapidly if it is a mechanical problem or has to do with "recoil and stuff" to quote you.

regards,
 
"had to single load as per range regulations"


I know that shooting range in l'Acadie... do like me and subscribe to another range.
 
death-junky said:
lol i had the EXACT same problem yesterday......
2 shots in a row it was pritty sweet feeling but still.............
and i hit the target with both bullets lol....
i think it had to do with the recoil and stuff.
talk to ya all later
Riley
Click to expand...
- we told you those 180's would cost you something- although it was probably a bump- just kidding- one of my 14's would do a whole mag full auto if you held the trigger just right- turns out when the armourer did the selector he left a burr ( it's a 3 btw) right where the roller was- 2seconds with a dremel fixed it- although why he used a torch instead of a grinder escapes me- maybe an acetylene junky
 
Doubling with the Garand/m-14 type rifles is a fairly common occurance. There is most likely nothing wrong with your rifle. It comes from too loose a grip when shooting from the bench. Treat it like a bolt action target rifle by barely touching it while shooting and use a feathery trigger pull, the rifle will double. It has to do with the recoil of the rifle causing the trigger finger to apply preassure to the trigger as the sear is resetting and the rifle fires as the bolt slams forward. It is quite cool to look up just as this happens (due to the unusual recoil) and see two pieces of brass in the air just a few inches apart. These actions are amazingly fast.

Use a firm and positive trigger pull at all times, making sure you "follow through" to press the trigger as far back as it will go, and this will not happen.

Best, cheapsk8
 
The Eastern Ontario Handgun Club (EOHC) in Cheney, Ontario has a nice covered firing point with 6 or 10 solid benches. The left side is 25 yds, then 100 yds and finally 200 yds. The last time I shot was a rainy Sunday morning and I was all by myself. The range is on the internet and new members are always welcome.

So, if your M305 doubled, or you massaged the trigger, or it accidently went full-auto, nobody would really worry. Just, don't start shooting before 09:00am.

This range has none of the "safety" rules strangely found only in Quebec. The club is so accomodating to Quebec shooters that the IPSC provincial matches are now held outside of Quebec.
 
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