Win M100 jams

hoffbill · February 15, 2009, 02:17 PM

have an M100 IN .243. The spent cartridge sticks in the chamber, sometimes barely, sometimes very tightly. usually will eject once or twice if chamber is lubed. No obvious visible damage. One gunsmith said it is unrepairable but not why? Any ideas on possible causes and fixes?

Ruger4570 · February 16, 2009, 11:45 PM

I can't say for sure either. I have a M100 Carbine in 284 that has always functioned perfectly... so far. I suspect it could be a couple of things, mostly with being dirty. Dirty receiver or a dirty gas system. From here I cn't trll. but I sure as hell would find another Gunsmith.

hoffbill · February 17, 2009, 08:20 AM

Thanks Ruger, I had reached the same conclusion about not using the gunsmith any more. I have carefully cleaned the rifle but it made no difference. The problem does not seem to be the action but rather the chamber. The spent case sticks very thightly, sometimes has to be punched out with a dowel. Is there any way to polish the chamber? This was a "truck gun" for several years so it was exposed to harsh conditions and may have some scratches in the chamber.

Doyle · February 17, 2009, 08:59 AM

You need to do some serious chamber cleaning. Here is one way. Get yourself a shotgun sized brass brush. For .243, I'm thinking either a 20 or 28 ga would work. A .410 is probably going to be too small. Take a pair of strong scissors or a set of diagonal cutting wire pliers and trim the bristles down into the shape of spent .243 casing (with the bullet end being on the side that attaches to a cleaning rod).

After making your chamber brush, insert your cleaning rod through the muzzle and insert your home-made chamber brush into the chamber and screw it in. Now, you can spin it and really clean out the chamber good. Use a little piece of plastic tubing (or maybe even a soda straw) to protect your muzzle crown while you are working.

kirbythegunsmith · February 17, 2009, 08:21 PM

If using Doyle's method (similar to my recommendations for shooters of semi-rifles to regularly brush their chambers) is not sufficient to make the operation reliable, a proper gunsmith (such as me) will include a chamber polish as part of a proper cleaning of the mechanism.
Semi rifles are more sensitive to incidental corrosion to the chamber walls, and any gunsmith worth his salt will polish all of the Remington pump/semi rifles he disassembles, for instance.

Kirby

hoffbill · February 18, 2009, 10:09 PM

Thanks Doyle and Kirby, I will follow your advice when I have time to do it and let you know how it turns out.

wachtelhund1 · February 19, 2009, 05:07 PM

hoffbill,
I have two M-100s. One had a jaming problem in one which I corrected myself. Cleaning is important, but M-100s are old and sometimes the springs weaken. You can do this yourself or take it to a gunsmith. Change the extractor spring to a slightly stronger spring. This is the spring on the claw that pulls the case from the chamber. For the action to function correctly, the extractor must hold the case firmly until the bolt moves all the way back and the ejector kicks the case out of the action. If the case is held too loose or slips from the extractor before bolt moves fully to the rear the ejector will not kick it out of the action.

Be careful removing this part as it is very small and will fly out when the retaining pin is removed from the bolt. Wrap the bolt in a white cloth when driving out the pin. I did this on both of my M-100s and have never had another jam. I have a supply of small gunsmith springs and just cut one of the same diameter slightly longer, maybe a half to three quarters of a turn longer.

Ruger4570 · February 25, 2009, 08:44 PM

Way back when I was in the Army, M-14 days, there were chamber brushes that had a plastic ratcheting affair attached to the brush. You would stick one end of the cleaning rod section into the hole and allow the bolt to close on the brush. You could rotate the brush a couple of degrees, reinsert the rod in a different hole to turn it some more. I have seen these for sale at several gunshows. I don't know if there is enough ejection port on a 100 for this to work though. Anyhow, just another thought.

February 15, 2009, 02:17 PM	#1
hoffbill Senior Member Join Date: February 15, 2009 Location: Texas Posts: 246	Win M100 jams have an M100 IN .243. The spent cartridge sticks in the chamber, sometimes barely, sometimes very tightly. usually will eject once or twice if chamber is lubed. No obvious visible damage. One gunsmith said it is unrepairable but not why? Any ideas on possible causes and fixes?

February 17, 2009, 08:21 PM	#5
kirbythegunsmith Member Join Date: February 15, 2007 Posts: 75	Details If using Doyle's method (similar to my recommendations for shooters of semi-rifles to regularly brush their chambers) is not sufficient to make the operation reliable, a proper gunsmith (such as me) will include a chamber polish as part of a proper cleaning of the mechanism. Semi rifles are more sensitive to incidental corrosion to the chamber walls, and any gunsmith worth his salt will polish all of the Remington pump/semi rifles he disassembles, for instance. Kirby __________________ [email protected] New gunsmithing website: http://theshotgunshop.net/ Articles containing valuable information are on every page.

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February 16, 2009, 11:45 PM	#2
Ruger4570 Senior Member Join Date: April 3, 2005 Location: Rochester, New York Posts: 2,136	I can't say for sure either. I have a M100 Carbine in 284 that has always functioned perfectly... so far. I suspect it could be a couple of things, mostly with being dirty. Dirty receiver or a dirty gas system. From here I cn't trll. but I sure as hell would find another Gunsmith.

February 17, 2009, 08:20 AM	#3
hoffbill Senior Member Join Date: February 15, 2009 Location: Texas Posts: 246	Thanks Ruger, I had reached the same conclusion about not using the gunsmith any more. I have carefully cleaned the rifle but it made no difference. The problem does not seem to be the action but rather the chamber. The spent case sticks very thightly, sometimes has to be punched out with a dowel. Is there any way to polish the chamber? This was a "truck gun" for several years so it was exposed to harsh conditions and may have some scratches in the chamber.

February 17, 2009, 08:59 AM	#4
Doyle Senior Member Join Date: June 20, 2007 Location: Rainbow City, Alabama Posts: 7,167	You need to do some serious chamber cleaning. Here is one way. Get yourself a shotgun sized brass brush. For .243, I'm thinking either a 20 or 28 ga would work. A .410 is probably going to be too small. Take a pair of strong scissors or a set of diagonal cutting wire pliers and trim the bristles down into the shape of spent .243 casing (with the bullet end being on the side that attaches to a cleaning rod). After making your chamber brush, insert your cleaning rod through the muzzle and insert your home-made chamber brush into the chamber and screw it in. Now, you can spin it and really clean out the chamber good. Use a little piece of plastic tubing (or maybe even a soda straw) to protect your muzzle crown while you are working.

February 18, 2009, 10:09 PM	#6
hoffbill Senior Member Join Date: February 15, 2009 Location: Texas Posts: 246	Thanks Doyle and Kirby, I will follow your advice when I have time to do it and let you know how it turns out.

February 19, 2009, 05:07 PM	#7
wachtelhund1 Senior Member Join Date: January 4, 2007 Location: pelican lake, WI Posts: 413	hoffbill, I have two M-100s. One had a jaming problem in one which I corrected myself. Cleaning is important, but M-100s are old and sometimes the springs weaken. You can do this yourself or take it to a gunsmith. Change the extractor spring to a slightly stronger spring. This is the spring on the claw that pulls the case from the chamber. For the action to function correctly, the extractor must hold the case firmly until the bolt moves all the way back and the ejector kicks the case out of the action. If the case is held too loose or slips from the extractor before bolt moves fully to the rear the ejector will not kick it out of the action. Be careful removing this part as it is very small and will fly out when the retaining pin is removed from the bolt. Wrap the bolt in a white cloth when driving out the pin. I did this on both of my M-100s and have never had another jam. I have a supply of small gunsmith springs and just cut one of the same diameter slightly longer, maybe a half to three quarters of a turn longer.

February 25, 2009, 08:44 PM	#8
Ruger4570 Senior Member Join Date: April 3, 2005 Location: Rochester, New York Posts: 2,136	Way back when I was in the Army, M-14 days, there were chamber brushes that had a plastic ratcheting affair attached to the brush. You would stick one end of the cleaning rod section into the hole and allow the bolt to close on the brush. You could rotate the brush a couple of degrees, reinsert the rod in a different hole to turn it some more. I have seen these for sale at several gunshows. I don't know if there is enough ejection port on a 100 for this to work though. Anyhow, just another thought.