FN SLP still won't cycle; "seal" the gas piston?

[BenL]

At the last 3 gun match, my FN SLP MK1 wouldn't cycle correctly. I hadn't cleaned it in some time, so I pulled it apart and gave it a good cleaning.

At yesterday's fun shoot, it was even worse.

I pulled apart again last night to check if the spring in the piston was broken (I was told to check and see if the spring was broken.) While the spring wasn't broken, the plastic spacer between the spring and the red retaining ring looks to be cracked and a little chewed up.

I've ordered a Browning sporting clays piston as a replacement (I've read that's a good replacement that is a lot more reliable) and I think I'm going to send out the busted piston to have it sealed. Has anyone else done this? Does it overgas the gun? I only use this gun for 3 gun, so it only needs to work with 2 3/4", 7 1/2's and occasionally low recoil slugs.

 

[BenL]

*bump*

 

[CrawfishStu]

What is it doing wrong exactly?
How many rounds through it?
What length barrel?
What brands of ammo have you had problems with?
Welded lifter?
Anything funny mounted to the gun or done to it to change recoil etc?

 

[CrawfishStu]

What/where are you oiling it?

 

[BenL]

What is it doing wrong exactly?
How many rounds through it?
What length barrel?
What brands of ammo have you had problems with?
Welded lifter?
Anything funny mounted to the gun or done to it to change recoil etc?

Only ~2-2.5K, mostly cheapo remingtons or federals 7.5's, and less than 100 low recoil slugs. 24" barrel. No welded lifter or dremeled loading port. 24" barrel. It's firing but not consistently ejecting spent hulls or loading new shells; it IS resetting the hammer, though. It will hand cycle with no problem.

No changes to the gun since last season except it sat a few months (from ~December to April) It went from 100% reliable to near 0% reliability after sitting for a few months. (between rifle/pistol/shotgun, I never practice shotgun, except loading.)

I gave it a good cleaning (it was filthy) and oiled with Slip 2000 EWL. This actually made it a little worse. It seems like the more I shoot it, the better it gets. First 8 shots will all have to be hand-cycled. In the next 8, 7 will be hand-cycled. By the fourth or fifth string, 2-3 will be hand-cycled. Slugs seem to run fine. Maybe the recoil spring in the buttstock?

 

[clandestine]

I wish I could help but I dont have intimate knowledge of these shotguns.

 

[BenL]

Actually, now that I think about it, maybe the spring in the buttstock got a little wet and has rusted.

I'll pull it apart and look at it tonight.

 

[BenL]

I wish I could help but I dont have intimate knowledge of these shotguns.

I'm surprised you don't. Apparently, these guns have a reputation for busted springs in both the gas system and the recoil system. While they're a great off-the-rack 3 gun shotgun, they just don't seem like they were factory-built to take the abuse 3 gunning can give.

Do you have an opinion on SureCycle systems?

http://www.surecycle.com/index.php/sure-cycle-systems/winchester/brn-01.html

It seems a very popular fix on on Enos's site is "sealing" the gas piston (essentially replacing the spring with a solid sleeve) and replacing the recoil assembly with a SureCycle system. That, and welding the lifter and grinding the loading port (which I won't do.) I'm concerned about over-gassing the gun, but an unreliable gun is useless to me.

 

[clandestine]

I'm surprised you don't. Apparently, these guns have a reputation for busted springs in both the gas system and the recoil system. While they're a great off-the-rack 3 gun shotgun, they just don't seem like they were factory-built to take the abuse 3 gunning can give.

Do you have an opinion on SureCycle systems?

http://www.surecycle.com/index.php/sure-cycle-systems/winchester/brn-01.html

Surecycles are great. I have put them in many Remingtons. They are great for waterfowlers who get saltwater in their gun. They may help you in this situation.

 

[CrawfishStu]

Mine hated it when I over oiled it. Everything in front of the breach runs almost dry with just a wipe of oil. I run the action pretty wet. That seems to work well for mine.

Recoil spring sounds like something to check. Sure you have the right piston set in it? Mine had the heavy set in it even though the instructions said the light set should be in the gun.

 

[BenL]

Surecycles are great. I have put them in many Remingtons. They are great for waterfowlers who get saltwater in their gun. They may help you in this situation.

Thanks, Chad. Ordered.

 

[BenL]

Mine hated it when I over oiled it. Everything in front of the breach runs almost dry with just a wipe of oil. I run the action pretty wet. That seems to work well for mine.

Recoil spring sounds like something to check. Sure you have the right piston set in it? Mine had the heavy set in it even though the instructions said the light set should be in the gun.

Yeah, it's the right piston (red.) Really disappointing. I've had it for a few seasons and this is the first issue I've had with it. I've run it oiled, dry, in the cold, heat, rain... never had an issue with it until now. I tried lightly oiled, heavy oil, and different types of oil. I just ordered a SureCycle assembly ($177; ouch, my ass) and a Browning Sporting Clays gas piston; hopefully, that will fix the issue and set the gun up to be more durable as well as reliable, since these are the two weak points for this gun. Apparently this setup will reliably cycle 7/8 oz loads, so should be no problem for my 1 1/8 oz loads.

 

[soup101]

Have you tried any higher velocity ammo, like Winchester AA Super Sports at 1300FPS?

 

[LeadSled1]

Looks pretty similar to my SX3 piston/spring. I thought the MKII was the SX3 and the MKI was the SX2? Anyways, recoil spring gets pretty cruddy. Have had mine in the field since 06 with no issues if I keep the spring lightly greased. Used in a lot of marine environments so it sees some salt. SureCycle has been on my list for a while.

 

[BenL]

Have you tried any higher velocity ammo, like Winchester AA Super Sports at 1300FPS?

No. I am sure that the higher velocity ammo would probably work fine, but I would like the shotgun to be reliable with cheap Walmart ammo.

 

[240 towles]

My local wal mart carries AA. runs about 7 dollars per box of 25 I think. I run federal through my semi auto as it has been the most reliable cheap ammo I can find. Remington falls right behind with Winchester bulk being just for pumps [jam o matic in my saiga even with reduced recoil load spring, adjustable gas regulator, advanced gas piston, and verified three gas ports in the barrel]

 

[BenL]

UPDATE

Yeah, it's the right piston (red.) Really disappointing. I've had it for a few seasons and this is the first issue I've had with it. I've run it oiled, dry, in the cold, heat, rain... never had an issue with it until now. I tried lightly oiled, heavy oil, and different types of oil. I just ordered a SureCycle assembly ($177; ouch, my ass) and a Browning Sporting Clays gas piston; hopefully, that will fix the issue and set the gun up to be more durable as well as reliable, since these are the two weak points for this gun. Apparently this setup will reliably cycle 7/8 oz loads, so should be no problem for my 1 1/8 oz loads.

I wanted to put in an update in case anyone finds this by searching the net looking or a fix to the same problem.

I installed the Surecycle and Browning piston and the gun runs great! 50 cheap Federal and Remington shells through it along with 10 low recoil slugs, and the gun seems fixed.