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Very Slow Lock Time

Posted: Tue Dec 18, 2018 12:45 pm
by greg
Hi All,
First post (other than new member intro) on this amazing site and am hoping you folks can help me with some concerns regarding my new, to me, 1936 mdl 81.

First off, I noticed lock time was very slow and thought the rifle needed a good cleaning and lube; since there where remnants of hardened lubricant all over the rifle. Upon disassembly, I noticed the hammer pin was bent so I straightened it. It is not perfect, but better than it was. The second issue encountered was during reinstalling the butt stock. I can feel that the Action Spring Plug actually hits in the bottom of the hole before the stock is fully seated. This makes reassembly of the stock screw difficult as a lot of force is necessary to push the action into the stock, before the stock screw can align itself with the threads in upper tang. I didn't like that 'cause I thought the butt stock could crack under use and during assembly, one stands a good chance of stripping the stock screw threads.

After clean, lube and reassembly I noticed the same slow lock time as before. My questions are, could the bent hammer pin be the culprit? Second, should I lengthen the hole in the butt stock so the action spring plug has a bit of clearance? I estimate the depth of the hole would have to be lengthened 1/16".

Additionally, upon shooting the rifle, I noticed my once fired Graff brass is a little beat-up at the case head, where the ejector comes into contact. All of the 20 rounds fired exhibit this trait and all rounds where inserted directly into the chamber for firing and not inserted into the magazine. Does this rifle behave better when rounds are stripped of the mag? I realize a picture of the bent hammer pin and case head would help you guys, but for the life of me, I can't figure how to do that.

Sorry the long winded write up and thanks in advance for your help!!

Greg

Re: Very Slow Lock Time

Posted: Wed Dec 19, 2018 6:54 pm
by Hcompton79
You do not want to deepen the hole in the stock at all if possible. The pin that holds in the action spring plug is only designed to do so during disassembly, the stock should be putting pressure on the action spring plug during firing.

The best way I have found to install the screw is to place the butt of the stock on the top of a table or your knee and press downward on the receiver to take up the tension in the spring, then start the screw by hand and finish with a screw driver.

If it is really to tight to do the above, then you could deepen the hole, but do so very minimally, as the wooden action spring plug should still be putting pressure against the inside of the stock recess.

As to your brass issue, I cannot see any reason why there would be an issue chamber loading versus from the magazine, although I have always loaded from the magazine on my 81, so I don't have any experience with this issue. The ejector is a spring loaded plunger much like an AR-15 bolt, so unless something is preventing it from moving rearward as the cartridge is chambered such as dirt or rust in the spring recess, it should move freely.

By the hammer pin, you do mean the pin that the axis of the hammer swings about on? If so, that could be causing the lock time issue, though I would try different ammunition if possible to eliminate that as a possibility. I would also shine a light in the charging handle slot and dry firing the rifle to see if the hammer is taking a while to drop.

Re: Very Slow Lock Time

Posted: Wed Jan 30, 2019 11:53 am
by greg
Hi HComp and thanks for the response. It's good to know the depth of the hole in the stock was designed to keep pressure on the action spring plug! I've been playing with the 81 a bit using only cast bullet reloads in the 1800 fps range and the rifle seems pretty accurate. Still, I've only fired the rifle by single loading directly into the chamber so I don't know if the 3 cast bullet designs I've used will properly feed from the magazine; and if the case head scuffing will go away once magazine fed. Now, because of this polar vortex and all the snow, I don't want to shoot it at all because I won't find my expensive cartridge cases until the spring. I really hope that woodchuck doesn't see his shadow 'cause I really tired of this weather. I'd take pictures of the back of the cases to share on this forum but posting pictures didn't work in the past so I'll not bother. I guess the scuffing is not really that bad but I really don't like to see all the flakes of brass on the face of the bolt.

The slow lock time I referred to was really the time it took for the hammer to fall after the trigger was pulled and not the overall cycling of the action (which IS slower due to my loads). Primers seem to be hit hard and aside from the slightly bent hammer pin, everything seems to work/look OK when I disassembled the rifle for cleaning and lubrication. I did attempt to straighten the hammer pin and will check it again next time the rifle is apart, which probably won't be for a while. Next disassembly, if it looks bent I may make a new hammer pin and see if that helps and I'll check the ejector pin again. You mentioned it should "move freely". It might, but that is one hell of a spring behind that plunger!

Thanks again for your input!!
Greg

Re: Very Slow Lock Time

Posted: Thu Jan 31, 2019 8:39 am
by kenhwind
IMO it would be better to feed from the magazine as it seems that the cartridge rim can slip under the extractor rather then be forced over it.
IIRC there should be a hammer bushing in these guns.