TargetTalk

I have a new steel Unit 1 with the lock back. I am getting a fail to feed consistently on the 4th round. The round starts in the chamber and the last round feeds out of the magazine and straight into the bolt face getting pinched at the breech face. The problem started with additional gsg mags purchased locally. I stopped using them and went to the Marvel supplied mag exclusively. The problem went away for a while and then started with that mag too.
I thought maybe it was a spring tension issue, so I loaded 10 rds in the 2 most problematic mags. I shot 4 matches last night doing this and only shooting 5 rds out of each mag. I did not have a single issue. The only related thread I could find was this one:

http://www.targettalk.org/viewtopic.php ... ght=marvel

It's a similar problem, but not the same. Any input or thoughts would be great. The plan right now is to make a spacer to go under the spring to increase the tension with only 5 rds in the mag.

What ammo? Did you by chance change ammo too?
How many rounds through the gun?
Last cleaned?
Don't know where you are located it's cold here and many 22s have feeding problems when it gets cold - use synthetic oil.

I'm shooting mainly Wolf Match or CCI SV, I changed my recoil spring to a lighter spring and all feeding issues went away except for an very rare one now and then with some bulk ammo.

Dave

The ammo was eley sport. It is the only ammo I have used. I have fed several hundred through other pistols without issue. I know that Marvel isn't testing with it anymore because of issues.
As to the recoil spring, that is why I referenced the other thread. The mystery however, is that it is always a 4th rd misfeed. Loading the mags full seems to have helped and possibly fixed the issue. Marvel is sending a lighter spring. If the gun isn't recoiling fully, wouldn't it mimic the same condition as tripping the slide release instead of slingshotting?
We'll call it less than 500 rds on the upper since new. I have not cleaned it yet b/c it functions fine otherwise and at 500 rds, seems premature.

does your mag seat all the way into the frame? if it has a lot of slop in its fit and you can push it about a 1/4'' or more in when its locked in place, the EGW oversize mag catch may solve your issues, it has for some of my friends marvel setups. look on the EGW website.

I had a similar problem with mine

Make sure mag is inserted all the way

I have and egw but did not fit it to my frame as the problem went away after 500 rounds.

If using composite mags debur the follower and top of mag with 600 grit sand paper, makes a world of difference.

I use case lube on all my bullets and clean the camber with a 25cal brush, bend it on a right angle 3/4 inch long. That gets the carbon out and helps a lot.

Also keep that top part of the slide oiled.

I thought about selling mine now it runs good.

I've set up several Marvel U1's. And provided info for a couple lockbacks that shoot in our local bullseye matches.

The magazines from Advantage Arms cured feeding problems in 3 lockbacks and two of the older Marvels.

They're 100% reliable unless you get a dud round.
The most reliable ammo is CCI SV and target ammo such as Eley Target (yellow box) or Lapua Center-X if the gun uses a 20lb mainspring.

I don't do anything to the ammo and I NEVER put oil on the top round in the mag.

I've shot 20,000 + rounds in Marvels, just tuning and using good ammo with very few malfunction and they always seem to be the ammo.

Here's info from Bob Marvel to tune the Marvels:

I set up the steel Colt marked magazines to function perfectly in two frames using the info on magazine lips.

http://www.guntalk-online.com/images/Ma ... ioning.pdf

Update:
As I said, with a full mag, I could fire 5 with no issue. I made a spacer to simulate the spring tension of a full mag and that didn't work. At all.
Last night I was able to tighten the mag lips as spec'ed in the Bob Marvel guide. That seems to have helped greatly, and I think with a bit more fine tuning, it will solve the problem.

Hopefully this is the last update as I believe the issue is resolved.

I read the Bob Marvel guide and tuned the mags accordingly. No difference.

I installed the EGW mag catch. Much tighter, but not the fix.

One of the guys at the club discussed it with me and suggested cutting down the magazine spring. I discussed it with Marvel and we agreed it might work.
I cut 6 coils (because with 6 coils off it felt about like a Ruger. Lol) off of the four mags that I had. The gun functioned flawlessly through four matches with the Eley Sport. I also duplicated my personal best of 278. Again, fingers crossed, the issue is resolved.

Marvel helped through this process and sent extra recoil springs and a mag spring in case it didn't work out. I am pleased with their product and service.