MisterB Posted January 20, 2018 Report Share Posted January 20, 2018 (edited) Not sure what the problem is, but I keep experiencing jams. I have multiple mags, but only use one 30 rounder, because I modified the mag hole and don't want to do that to any more mags than I have to. I've gone 3 full 30 round mags full of shooting without issue, but then it started to jam so I tore it down and cleaned and lubed it up, but it's still happening. I've tried loading just 10 rounds, but it still happens. Is it maybe a weak mag spring? Should I take more off the mag catch hole? Any other ideas? Other than that, it was a great day shooting out on my property Edited January 20, 2018 by MisterB Link to comment Share on other sites More sharing options...
95mustang Posted January 20, 2018 Report Share Posted January 20, 2018 what springs are you using for recoil springs ? Link to comment Share on other sites More sharing options...
MisterB Posted January 20, 2018 Author Report Share Posted January 20, 2018 what springs are you using for recoil springs ?The stock ones it came with from the factory Link to comment Share on other sites More sharing options...
95mustang Posted January 20, 2018 Report Share Posted January 20, 2018 (edited) ok ..I found that mine only likes the heavy duty OEM original springs best . But I have discovered the trick to making mine run flawless was to make sure the magazines have a little bit of up and down movement to them when locked in , wiggle room if you will .without that little bit of wiggle the bolt rides to hard on the loaded mags and it slows it down enough that bullets dont have a prayer to make it up the feed ramp .you need enough wiggle room to ease the pressure on the bolt while still keeping the mag high enough in the engagement so the bolt can strip rounds from the mag .take a round file to the top edge of mag catch hole , it only takes a few strokes to get the wiggle you need watch some you tubes of a thompson running full auto in slow motion .........that magazine needs to fit loose as a goose Edited January 20, 2018 by 95mustang Link to comment Share on other sites More sharing options...
deerslayer Posted January 20, 2018 Report Share Posted January 20, 2018 You need to describe your jam. Round partially fed with nose of bolt against the side of the case, double feed, bolt almost closed on round but firing pin forward. A GOOD picture and description will help. See if each jam is the same. Or coming from same size of the magazine. Most jams are result of mag sitting too low or bad fit of firing pin. Link to comment Share on other sites More sharing options...
Devious6 Posted January 20, 2018 Report Share Posted January 20, 2018 I'd also add that it's always good practice to smack the magazine against the heel of your shoe or another hard surface to ensure the rounds are seated against the back of the magazine - with the old M16s and M4s, we'd tap the mag against our helmet before putting it into the rifle. A round too far forward can get caught by the bolt. I have only had one jam with my AO/Kahr M1SB and I'm sure this is what caused it. Link to comment Share on other sites More sharing options...
Oldtrooper Posted January 20, 2018 Report Share Posted January 20, 2018 I was surprised when I sent all my stick magazines to Dan Block that of the 11 magazines I sent to him, 10 had feed lips out of spec ... Dan corrected them and I have not had a failure to feed since ... Something to consider. Link to comment Share on other sites More sharing options...
MisterB Posted January 20, 2018 Author Report Share Posted January 20, 2018 ok ..I found that mine only likes the heavy duty OEM original springs best . But I have discovered the trick to making mine run flawless was to make sure the magazines have a little bit of up and down movement to them when locked in , wiggle room if you will .without that little bit of wiggle the bolt rides to hard on the loaded mags and it slows it down enough that bullets dont have a prayer to make it up the feed ramp .you need enough wiggle room to ease the pressure on the bolt while still keeping the mag high enough in the engagement so the bolt can strip rounds from the mag .take a round file to the top edge of mag catch hole , it only takes a few strokes to get the wiggle you need watch some you tubes of a thompson running full auto in slow motion .........that magazine needs to fit loose as a gooseI just tried that and loaded 5 rounds in the mag and cycled it, but it's still doing it. In fact, it may be worse now. If I press up on the mag while cycling the action, it doesn't seem to jam Link to comment Share on other sites More sharing options...
MisterB Posted January 20, 2018 Author Report Share Posted January 20, 2018 You need to describe your jam. Round partially fed with nose of bolt against the side of the case, double feed, bolt almost closed on round but firing pin forward. A GOOD picture and description will help. See if each jam is the same. Or coming from same size of the magazine. Most jams are result of mag sitting too low or bad fit of firing pin.It's a single feed, and the round basically gets stuck sideways between the mag and the opening to the barrel. The bolt pins it against the barrel opening. Here's a round that had this happen Link to comment Share on other sites More sharing options...
ppgcowboy Posted January 20, 2018 Report Share Posted January 20, 2018 A modified mag. Have you tried a non modified mag made for semi-autos? Link to comment Share on other sites More sharing options...
MisterB Posted January 20, 2018 Author Report Share Posted January 20, 2018 A modified mag. Have you tried a non modified mag made for semi-autos?No, I don't have any. Link to comment Share on other sites More sharing options...
Paladin601 Posted January 21, 2018 Report Share Posted January 21, 2018 sounds like you elongated the hole to much, try a kahr mag and see if that changes things Link to comment Share on other sites More sharing options...
vanvock Posted January 21, 2018 Report Share Posted January 21, 2018 I'm having the same prob. I just got a used GI mag & filed it for a tight fit but still got jams too. I have found that if I hold onto the mag instead of the foregrip while firing it works great even with the loose fitting Kahr mags. What does that indicate? Link to comment Share on other sites More sharing options...
MisterB Posted January 21, 2018 Author Report Share Posted January 21, 2018 This is all starting to make me thing I may have been wrong to think that modifying the mag was best, and instead I should modify the mag catch on the gun? Does anybody have any pictures that show how the mag catch should be filed down? Link to comment Share on other sites More sharing options...
deerslayer Posted January 21, 2018 Report Share Posted January 21, 2018 Mister B, I think your mag lips are squashed down or the mag is sitting too low. Bolt is riding over the rim of the cartridge. If your handy with tools try bending the lips up. Link to comment Share on other sites More sharing options...
MisterB Posted January 21, 2018 Author Report Share Posted January 21, 2018 Mister B, I think your mag lips are squashed down or the mag is sitting too low. Bolt is riding over the rim of the cartridge. If your handy with tools try bending the lips up.Awesome. Thanks, I'll try that Link to comment Share on other sites More sharing options...
MisterB Posted January 21, 2018 Author Report Share Posted January 21, 2018 Mister B, I think your mag lips are squashed down or the mag is sitting too low. Bolt is riding over the rim of the cartridge. If your handy with tools try bending the lips up.I tried this today, and things look promising. I won't know for sure until I shoot it, but it cycles and chambers with a completely full mag, and with just a few rounds in the mag. Link to comment Share on other sites More sharing options...
MisterB Posted January 23, 2018 Author Report Share Posted January 23, 2018 Took it out to the range. Unfortunately, same problems. Going to drop it off at my gunsmith to get it sorted out. Will likely go ahead and have him modify the mag catch hole, and I'll use unaltered GI mags from here out Link to comment Share on other sites More sharing options...
vanvock Posted January 23, 2018 Report Share Posted January 23, 2018 Let us know what he finds, how it works out. Link to comment Share on other sites More sharing options...
deerslayer Posted January 28, 2018 Report Share Posted January 28, 2018 Beware... 80 year old mags will likely have squished feed lips too. Link to comment Share on other sites More sharing options...
MisterB Posted January 28, 2018 Author Report Share Posted January 28, 2018 Beware... 80 year old mags will likely have squished feed lips too.The mag I have been using all along is an 80 year old WWII mag. I don't even own a Kahr mag. I modified the feed lips, but it's still jamming Link to comment Share on other sites More sharing options...
Paladin601 Posted January 29, 2018 Report Share Posted January 29, 2018 (edited) This is all starting to make me thing I may have been wrong to think that modifying the mag was best, and instead I should modify the mag catch on the gun? Does anybody have any pictures that show how the mag catch should be filed down? why, you can screw up the mag catch as well by removing to much metal You did not get ANY factory mags with the rifles purchase? Edited January 29, 2018 by Paladin601 Link to comment Share on other sites More sharing options...
MisterB Posted January 30, 2018 Author Report Share Posted January 30, 2018 This is all starting to make me thing I may have been wrong to think that modifying the mag was best, and instead I should modify the mag catch on the gun? Does anybody have any pictures that show how the mag catch should be filed down? why, you can screw up the mag catch as well by removing to much metal You did not get ANY factory mags with the rifles purchase?It came with one Kahr mag, but I traded it for a WWII mag, and then purchased additional WWII mags. Link to comment Share on other sites More sharing options...
katanafred Posted June 6, 2022 Report Share Posted June 6, 2022 Hello - I'm new to the forum and have really enjoyed reading about everyone's experiences and ideas for minimizing jams! I purchased the Kahr Semi-Auto THOMPSON M1 CARBINE. I switched out the OEM springs for the Howell kit and have been very pleased with the overall performance difference! I have three of the 30 round stick magazines from Kahr. I fired about 100 rounds among all three magazines and experienced more than a few jams, but all in all not as bad I was expecting. That being said, I called Kahr and tried to get specs on the magazine lips which the tech I spoke with did not know or didn't understand. He did recommend elongating the magazine catch holes to help seat the magazine better and raise how the magazine sits. So should I be elongating the bottom of the hole or top of the catch hole? My simple ex-grunt mind seems to think that the bottom hole should be elongated, but I am open and will appreciate any suggestions. Thanks! Link to comment Share on other sites More sharing options...
68coupe Posted June 7, 2022 Report Share Posted June 7, 2022 Katanafred, As installed in the gun, you would be removing material from the TOP of the catch hole. Be very careful, as once you remove material, it can't be replaced, and can never be made to look right, even with skilled welding. Remove a little at a time, checking fit between filings. Just my 2cents. Karl 1 Link to comment Share on other sites More sharing options...
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