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LoboMike

Sporter problem

10 posts in this topic

At a shoot this month we had an interesting experience with

my Johnson Automatics M1941 Sporter. First I fired 10 or 15 rounds

without incident and excellent functioning.

Fellow shooter tried the rifle and had an issue, the rifle fired,

cycled and didn't fire on the next loaded round. Did this maybe three

consecutive times. Unfired shells showed a very light dimple, which I

believe was from the firing pin inertia upon bolt closing. I found the

receiver/bolt a little dirty, so cleaning and lubing appeared to solve

the problem.

I think a combination of dirt and "soft" shooting absorbed much of the

recoil operation resulting in the hammer never coming fully cocked.

IMHO!

Second issue was with same fellow shooter the rifle did double once.

This puzzles me, any thoughts? I have not been able to duplicate this

event. Could this be operator induced, as he was unfamiliar with a Johnson?

TIA Mike

<_<

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Several items to check: Inspect firing pin and be sure the little ring is fastened into the notched place and the small spring tail is hooked under the ring. Be sure the firing pin stop is installed. Check the trigger block assembly and see that the small cross pins just above the trigger are even on both sides. They are supposed to be staked but if not, one end of the pin can fall inside the assembly and gun can slam fire. Ocassionaly, I have seen a gun mis-function because the shooter was holding it too lightly and it moved away from the recoiling bolt as it came back. Also sporters seldom have the recoil key for the recoil tube in the right location. They are usually plugged over and it is hard to measure distance from it to the key over trigger. Design distance is 8.00". The location of the recoil system is critical to proper functioning.

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LoboMike, I had some experiences with this same problem. First do exactly what

Joseph Scott recommends. Two, you do not say what type of ammo was used by both of the shooters. This normally makes no difference as this rifle was tested years ago using bullet weights of 110 to 220 grains commercial loads and all military weights without a functioning problem. Keep in mind that this rifle is recoil operated and needs to have a certain resistance against the reciprocating bolt to cycle. It is listed here as "weak shoulder" offering no resistance. In hand gun shooting this same problem is called "limp wristed" holding and has nothing to do with gays. Three, the fact that you are getting dimples on the primers indicates that a slam fire is taking place and causing the doubling. I found that in my rifles they tended to double with lighter weight bullets especially in the 7X57 loads. Four, On the "click issue", it sounds as though the bolt is not going back far enough for the sear to engage the hammer and lock it until depressed. Give us some more poop and we will see if we can correct this problem. Cordially, Alasdair

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On page 103 of Bruce Canfield's "Johnson Rifle" book. it shows a curious photo of "one handed" firing of the light machine gun which shares similar mechanical characteristics as the rifle.

So this would might be viewed as not needing a whole lot of shoulder in the shot. None the less Melvin is straight armed and the machine gun has a pistol grip.

Anybody ever try firing a Johnson from the hip?

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OK gentlemen her's what I have so far, and thanx for all the help.

The ammo was Talon M2 ball, unfortunately I do not have the bullet weight. I believe this is supposedly surplus USGI ammo "re-assembled". It is marked LC-53.

Both problems occurred with the same 1st time JA rifle experience. I have not been able to reproduce either issue. I agree on the bolt not cycling enough to engage the hammer/sear. I attribute this to "weak shoulder" shooting.

The doubling continues to evade me. The checks of Joe's items revealed no problems, with possible exception of the measurement of the recoil key. It is plugged and appears less than the desired 8" and I have to go back and check the firing pin stop as I forgot that one.

I suspect the primer dimpling (very light) is firing pin inertia on bolt closing. Speculating while the firing pin assembly looks fine the spring may be a touch weak permitting contact with the primer and the double may have been a case of enough inertia to set off a primer. Reasonable?

I believe I have an extra spring to compare/test, if not I hope they're available, Joe?

I like the rifle and compare it equally for fun shooting to my military JA M1941. Am I going down the right track?

Thanx again, Mike

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LoboMike, The ammo sounds as though there is no problem. Keep in mind that this rifle was tested to handle everyting from 110-220 weights both military and commercial. It sounds as though your cocking problem has subsided. When my rifle doubled, I even put two inertia recoil supressing springs on the firing pin which had no effect in stopping the slam fire and dimpling. I even changed the firing pins with extras I have with no effect. What I concluded was the main recoil spring was the problem. It should rest at 12 inches in length out of the rifle. If less, it has taken a set. When I replaced my set and worn recoil spring, the firing pin springs could not supress the increased celerity, which caused the bolt to go into battery harder causing the slam fires and dimpling. Wow, there is a run on sentence. Have you changed this spring? When I put my old tired spring back in the slam fire stopped. The only problem now is you have to have no one on your right less the brass exiting will kill them. It appears that when you change one part, you change the entire functioning of the rifle through a domino effect.

Keep us posted, cordially Alasdair

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If the recoil tube is positioned too close to the receiver, this can limit rearward bolt travel, and occassionaly, not hook the hammer. I see this wrong position, all the time in sporter stocks. Most of the sporter keys were just put through a hole and usually have fiberglas resin holding them. In the old days, they didn't understand how important this location is. Do you have access to an original stock with tube that shoots well? Try one if possible. Be sure to inspect inside recoil tube with a bore light for corrosion/pitting. Also be sure the barrel latch spring is clean and lubricated, this returns the barrel forward to home position. If it is slow, barrel may be rearward when shell enters chamber and gives the firing pin contact although it is designed not to do this. If mainspring has grease on it, remove grease and use oil. Trouble-shooting without other parts to swap out gets tough.

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OK here's what I got;

Where Joe has "the rear of the extractor cut comes within 3/16" of rear of op handle cut in receiver", my Sporter has 3/8" and where Joe has ", the distance from bolt face to front of receiver opening is 4.050" my Sporter appears to be approx. 3 7/8".

So Ithink this confirms the recoil tube is too far forward by approx. 3/16". Joe how did this compare with the Sporter you examined?

What's my next step? How do I go about fixing this, hopefully without damaging the butt stock? <_<

Can I take the butt stock from my military JASR to further test this issue?

Thanx again gentlemen, Mike :blink:

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One of my sporters was shooting in a simular manner, I did replace the stock with a Military from Joe and never had the problem agian. I purchased it with all hardware allready installed by Joe and all I did was a 2 step process of staining to match the exact color of my other miltary's and then bolted it on. Simple. My sporter stock was also not set up corectly and the tube was closer than the miltary one Joe sent. I don't know if that is your problem, but it was mine.

John Schlegel

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