Help us Identify this jam!

[Kyle O]

The jam happens as the gun is returning to battery, there is no issue with the gas system, it locks back fine, and cycles fine, but one out of each tube seems to end up just like this.

The shell is pointed ever so slightly to the right, and down, and catching some of the extractor notch, it leaves a good gouge in the end of the shell.

When the action is cycled by hand, the shells point up, and into the chamber, but the jam shows the base of the shell all the way to the top and kind of nosediving back down. This happens with multiple types of ammunition, so we have ruled that out.

Here are some photo's.

Please help diagnose!

[00bullitt]

Run a quick search......thats been covered twice before on here. Common amongst the SLP and SX2/3 platforms.

[Jadeslade]

How many shells have you run through that gun? Any mods to your gun?

[Kyle O]

Run a quick search......thats been covered twice before on here. Common amongst the SLP and SX2/3 platforms.

I did search FN SLP jam, and got zilch, if you would be so kind as to direct me to the threads.

We shot with I think 6 of these guns today (local match), roughly 100 rounds each, and none jammed but this one. I wouldn't think of it as "common?" I use the same shotgun, and have never had a jam.

How many shells have you run through that gun? Any mods to your gun?

Not sure about the round count, nothing unreasonable though. It has had the lifter welded by c-rums. Also, a nordic bolt handle, and +1 nordic extension. Sorry, should have included that info in the beginning.

[ChuckS]

Kyle,

This picture should tell you the whole story

http://www.brianenos.com/forums/index.php?showtopic=106974&view=findpost&p=1230621

Later,

Chuck

[Kyle O]

Thank you for the guidance Chuck

Brandon, are you seeing this?

[texbran]

It looks like we need to smooth the notch off abit.I going to get the gun out of the truck and look at that again.I might have to make a trip back to the country tonight.

[Kyle O]

Bring it on bud.

[texbran]

The wife just said something like.Have you not had enough today.I just told her no its only been 16 hours sinse we started this morning.We will have to wait until tomorrow.I'll see you after church sometime.

Brandon

3 gun is great even if you only have two and a half guns like me today.

[ChuckS]

Thank you for the guidance Chuck

Brandon, are you seeing this?

Guys,

I am thinking about getting one of these and, as you can tell from my other post, I have been searching the crap out of SLP. Please keep me posted of any other observations you may make!

Later,

Chuck

[ap3]

Yes, it does help to take some material off the lifter, and you will want to do this anyway to help with your reloads.

Also, make sure the lifter is square. FN's and Browning can get out of alignment sometimes. The timing of the loading is really important and the lifter alignment can affect the timing as well as the basic loading of a shell. It really sounds like that lifter is dragging on something or out of alignment, and hand cyclying will not show it because the timing is different.

A final footnote,an FN as well as most shotguns need about 3-500 rounds of break-in, before they will quit doing freaky things.

[texbran]

I don't mind the 3 to 5000 rounds,but I don't won't to do that many with the thing jamming every 4 rounds.How would you realign the lifter? We had 5 or 6 fn's in our squad at a match yesterday and mine was the only problem.

Brandon

[usp45ss]

Here's a little more info on the gun. It is my old gun. It probably has 1500 rounds through it. Loading port is smoothed and polished. The lifter was welded up by C-Rums with a relief cut in it for clearing a double feed. I had the same problem with it in the Ozark match. Jamming every 4-5th round. I took it home and polished that surface near the extractor groove. I didn't round it off like Tod's pics but I did polish it smooth. It ran 100% after that for 200-300 rounds before I sold it. I thought I had fixed the problem but I guess not. Looking at the jam yesterday, I think that flat surface really needs to be rounded and polished.

[00bullitt]

There are some other issues that create that problem that I was able to see using a high speed camera. There is alot of side to side lateral motion of the shell as it enters the chamber. The lifter is used to stabilize that motion. I've noticed that the lifter has a lot of lateral side to side movement as it guides the shell up. Once welded it also lacks the forks that help stabilize some of that movement. I make a dish in the end of the lifter where the forks once were to help guide the shell. Shimming the lifter to alleviate that movement also helps tremendously.

But that problem is quite common in these platforms as well as the Benellis. I've seen it in most shotguns out there.

[Kyle O]

I would LOVE to see that high speed footage, if you could post it!

The first thing I thought during our initial exam was,"it would be nice if we had a high speed camera"

Thanks for the insight double ought.

[P.E. Kelley]

This problem gets easier to solve once you wrap you head around the idea that the "feed ramp" is the barrel extension at 12 o clock.

With that understood the role the lifter plays as guide is less significant.

My fix has been to replace the carrier lifter spring with a spring with a thicker wire diameter (.002")

A stronger spring will snap the shell up to the "feed ramp" and the curvature of the barrel extension

keeps it centered during the transition into the chamber.

If I remember correctly it is an English 5-5 spring. Brownell's sells a kit of these English springs.

I believe some guys are using a pair of some other gun spring, sorry I do not recall what one/s.

Good luck

Patrick

[00bullitt]

Patrick is right.....that is another aid in getting the shells to feed right. The more tension the lifter has to lift the shell straight up, the better it will feed and eliminate lateral motion as well. I used a piece of another lifter spring and added it to increase pressure. I have been looking for a suitable replacement spring for the FN platform. So far the standard spring plus a quarter of another has worked well for me.

Its always a balancing act with these things.

[00bullitt]

I would LOVE to see that high speed footage, if you could post it!

The first thing I thought during our initial exam was,"it would be nice if we had a high speed camera"

Thanks for the insight double ought.

Don't have the footage. We reviewed it on his playback monitor. I did not have any means to retain the footage that day. I wish I did. It was cool video.

[ap3]

I don't mind the 3 to 5000 rounds,but I don't won't to do that many with the thing jamming every 4 rounds.How would you realign the lifter? We had 5 or 6 fn's in our squad at a match yesterday and mine was the only problem.

Brandon

I can't really add much to what Tod suggessted. I did the same thing of creating a dish for the shell in the lifter and polished it up to 600grit

With the bolt closed turn it upside down and observe the travel of the lifter. It should just barely clear the lifter/bolt release in the side of the gun. You can also take some material off the end of the forks in case it is dragging at that point or simply so you have more clearance for your thumb while reloading.Study the side of the lifter as Tod suggessted and make sure they are not bent out allowing the shell to move around too much left or right while on the lifter.

Whah=tever the part is that is out of spec is a very small problem, so your going to have to really carefully study the process to find the deviation. If you just absolutly can not get it fixed you are welcome to send it to me and I will work on it.

Didn't see Patricks post at first as he makes a great point. The springs on the lifter and and even the lifter/bolt release can be adjusted to improve performance. Timing is everythng with these shotguns.

Edited December 12, 2010 by ap3

[DocMcG]

+1 on the polishing!

I was struggling with this exact issue after making some mods to my SLP. I received the same advice - polish the sharp portion and inside of the chamber at the extraction slot (Thanks again 00bullitt!). This fixed the issue, however, I did go one step farther. I had my gunsmith build up the right hand side of the lifter to serve as a guide wall to roll the shell back to the left and into the chamber if I was canted right. Since then I have shot the gun on its side, ejection port down, and still have zero issues.

Good luck!

Kyle

[texbran]

Well we got the gun going .We rounded and smoothed the area around the notch.It didn't take much at all.Shot rounds through it and didn't have any trouble.

Thanks for all the help.

Brandon

[Bryan 45]

Joe Satterfield tunes his with a 20oz framing hammer. He's messed with the SLP enough to be able to help if you have additional issues.