Overall, been an Underwood fan like many others on the forum. My #1 Underwood Self Defense ammo of theirs is the 165gr JHP Gold Dot. I like this one a lot!
The ammo I've had trouble with, getting stuck on the ramp while feeding is their 200gr TMJ. I honestly don't know if the company has discontinued it or not. All I've experienced with 100 rounds is an inordinate amount of failure to feeds.
Running stock, my G20SF feeds the DT 200gr Hard Cast very well. It didn't like the 220gr Hard Cast.
Maybe others can chime in... I think the Underwood 200 gr. TMJ in question, appears to be... too long?
I never tried the 200 grain tmj from Underwood in my SF.
It feeds 200 grain XTP without a hitch though. It also feeds CCI Blazer 200 grain.
Maybe give Kevin Underwood a call? He may have some good advice, or else he might want to tweak his ammo a bit.
Good luck and let us know how it goes.
Can you actually measure the overall length of the ammo? 1.2500" - 1.2550" should feed fine from the G-20 SF. I have seen others experience that same issue of FTF and hanging to the side of the feed ramp.
The impulse being higher on the Underwood over other factory ammo, could increase slide velocities. Use of an aftermarket RSA could help control the slide velocity to the rear and add some potential to feeding with forward closure.
I use the Wolff Gunsprings non captive system and 22 lbs spring for mine!
Quote from: The_Shadow on October 08 2016 12:04:42 PM MDT
Can you actually measure the overall length of the ammo? 1.2500" - 1.2550" should feed fine from the G-20 SF. I have seen others experience that same issue of FTF and hanging to the side of the feed ramp.
The impulse being higher on the Underwood over other factory ammo, could increase slide velocities. Use of an aftermarket RSA could help control the slide velocity to the rear and add some potential to feeding with forward closure.
I use the Wolff Gunsprings non captive system and 22 lbs spring for mine!
I'm out of the ammo unfortunately. I also tried this same ammo last year with the 22# recoil spring and tungsten guide rod. Had the same problems. That's why I took out the last box of fifty and ran it stock. No difference. Could very well be the length and the shape of bullet with flat nose? I thought some here might have noticed the same.
What you are experiencing is similar to this thread (G29): http://10mm-firearms.com/general-discussion/g29-failure-to-feed-hard-cast/
I have shot 215 JHP and 220 LSWC bullets out of my stock G20 without problems.
I have never shot Underwood, Buffalo Bore, or Double Tap out of my gun.
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I have never tried the Underwood 200gr tmj either, but my G20sf also loves underwood 200gr hard cast, but balks at the 220 hard cast.
I have a box so here it is:
Uw 10mm 200 FMJ - 1.254
Uw 10mm 200 XTP - 1.252
My Glock 20SF LW Longslide doesn't really like the 200 or the 220gr from Underwood, and in general that gun and often my 10mm AR don't any heavy bullet 10mm ammo with zero to no crimp - that stuff will hang on the case lip like a mad man. Some of the bullets used 2015 or so by Underwood have been discontinued because so many people have feed problems.
Oddly I never, ever have any feed or cycling problems with my own loaded ammo. Sort of runs contrary to lay contrary opinion, interestingly enough.