Shockbuff Jams

[Bigbadaboom]

 I have two STI Edge style limited guns that are almost identical. Both are long dust cover, heavy Schuemann ultimatch .40 cal. barrels, unique cut slides, STI tungsten guiderods and plugs, ect. ect. triggers, hammers, sears and all other fire function part in the guns are the same. Here is my problem! one will not run with a shockbuff and the other runs great with or without one! I did not build these guns but the man that did realy knows his $#!+ when it comes to guns, I'm talking John Browning reincarnated, and it even has him stumped. When I first got the gun it was parkerized and would run fine with a shockbuff and 12.5lb. spring but after I got it hardchromed it would fail to feed ( Round will nose down into the bottom of the barrel ramp). It does this with all my mags, all my load lengths ( from 1.130 to 1.20 ). It does this with recoil springs from 12.5 to 16 lbs.. Without a shockbuff the gun runs like a Rolex but as soon as I put one in it the jams return. All tolerances look to be almost the same on both guns except that the slide on the jamming gun comes to the rear a hair farther than the other (about .040 farther). Any help with figureing this out would be more than appreciated.

[bountyhunter]

The shok-buff reduces the total length the slide draws back (shortens the cycle stroke) which:

1)  Reduces the time the next round has to feed.

2)  Reduces the space in the area the round is coming up into.

What's wierd is you said the jamming gun's slide cycles farther back?  I'm wondering if the hardchrome plating tightened up the clearances in the mag well and changed the mag position slightly?

I have heard MANY stories of people with a certain model gun which would not tolerate a shok-buff and the next guy's loved it.  I was told it can usually be fixed by milling the slide a bit to allow it to go back farther (in other words, relieving it so the cycle distance is the same with the buff as it was before).  Most people just throw the buff away which is a shame because it reduces frame hammering.

I think the most likely scenario here could be that the plating has tightened up the fit on the slide a shade.  It may cycle without the buff because bouncing off the frame (metal to metal contact) gives the slide enough rebound energy to strip the round and go back into battery.  The shok-buff does absorb energy (that's how it works) so the slide may not have quite enough to cycle properly when the buff is there.

[benos]

Bigbadaboom,

I know there are detailed topics in this forum on this issue. Try a search using the word "shok" - and search for the "keyword in post," in this forum. You should find some useful info, not only on shok buffs, but just finicky 40 feeding in general.

be

[bmz]

I'm an avid user of shockbuffs, believing that this will at least lengthen the life of my gun.  But i do believe in preventive maintenance as i clean the gun after each session, being able to inspect the condition of the shockbuff.

Any appearance deviating from the norm, it should be replaced.  As for it causing jams, it probably would depend on a case to case basis.  Maybe the tolerances are too tight thereby slowing the action of the slide as it rubs on the  shockbuff.

I don't believe that adding it would short stroke the action but am inclined more on the tolerance factor.

And there are different brands out there, some better than others, however i have found them to be sensitive to heat or deteriorate during long storage.

[benny hill]

all my guns run w/ buff's.  the trick is to make sure they are trimmed down smaller than the guide rod heah[no drag] then install a great mag spring.[ ISMI]

[Nate]

Benny, my story is much like BDB except my matching guns are SV's. The failure is exactly the same. I even cut the buffs down to match the guide rod. I tried some lighter and heavier springs with some success except I shoot my best with a 14 Lb. spring. Here is the kicker. The gun belonged to someone else who shot it for a year with a buff and it ran like butter. It really doesn't matter because it runs great without the buff so I will run it that way, but I thought if you got someone with a simialr story you can have that in your mental library. My only thought was that I may have a worn mag release or mag but it happens with all but one mag. I might try the release designed to hold the mag up a bit higher in the gun. Any idea who makes it? Nate

[benny hill]

maybe the gun just does'nt like you.

[Singlestack]

maybe the gun just does'nt like you.

LMAO

Thats some hardcore stuff, lol

[megaman]

why not try talking to it? they say it works with plants that fail to thrive...

[2alpha]

How hard you hold the gun makes a difference that will show up under marginal circumstances. That's why a gun will run for one person and not the other. No way is hard chrome thick enough to make a difference in the mag well. It is kinda sticky when new and can slow the slide down until it gets broken in though.

[TBF]

Nate,

Seems like JP made a mag catch that fits your description.

Travis F.

[jersey boy]

If it runs great without just take it out and use it as a back up gun. How hard is that you can only shoot one at a time anyway. Right?

[Tuner-1911]

After reading this one and studying it a while, it sounds like a magazine issue.

First...Does it happen on all rounds or just the top two or three in the magazine? OR...does it happen more frequently on the lower rounds

when spring tension lessens?

Second. What type magazines/ followers are you using?

Top rounds...when the spring tension is high...sometimes causes the drag on

the upper rounds to be at a point that the follower rocks downward at the

front. The reduced slide travel eliminates just enough slide momentum to

force the round up the ramp and into battery....and the reason that it doesn't happen with the other pistol is a slight difference in feed ramp angles between the two guns...The jammer has a steeper angle. One degree can

make a difference.

If it happens on the lower rounds, when spring tension is lowest, may be

due to the slide timing...it begins the trip back toward battery earlier, before

the magazine spring has enough time to get the upcoming round nailed

to the feed lips. Removing the buff gives the magazine a split-second longer

to get the round stable.

I'm assuming that you have a ramped barrel. Maybe your smith can do a

good polish job toward the top of the ramp beginning at the point that the

bullet nose first makes contact with it with the goal of lowering that angle

just a fractional amount.

Hope this squashes your bug...

Tuner