Cycling probs after slide lightening

[Ed Robinson]

(I also posted this on the open gun forum. I wanted to get it in front of as many eyes as possible, Ed)

Gun is a Para P14 5" comp'ed I shoot Bianchi with. Was getting a weird reverb/vibration on the barricade and decided to lighten the slide a little. Bobby at FGW did the mill work and Tri Topped and cut 3 lightening slots in the top of the slide. Cut it down to right at 10oz I believe he said. My old load was 4.8gr 231 under a 125 Missouri in 38 SC Starline brass which was very accurate and 100% reliable. After lightening, I tried it with the recoil spring I had in it(which I think was 8 or 9lb). Would not cycle. I put in a new 7lb spring and tried again. No dice. Ejected 1 of 7 rounds. Should I go on up on my load to get cycling back or go to a lighter spring. Common sense says a lighter slide would have dictated a heavier spring given the same load but this one did not work out that way. This is my first lightened slide( lightened this much) so I'm still in the learning curve.Did removing mass, which removed momentum cause the problem? What to do, what to do?

[outerlimits]

could be a number of things. is it failing to eject, or failing to chamber a round?

with a lighter slide mass, your mainspring may now be a bit too much. another culprit once you lighten a slide and run a recoil spring that light could be the firing pin retainer angle. i have a slide on an old steel gun that is REALLY hogged out. i run a 5 lb recoil spring and had to mod the angle of the firing pin retainer to get it to unlock smooth enough. if it's not locking, there are other issues.

[ParaGunner]

Was the slide refinished?

[goneracin]

(I also posted this on the open gun forum. I wanted to get it in front of as many eyes as possible, Ed)

Gun is a Para P14 5" comp'ed I shoot Bianchi with. Was getting a weird reverb/vibration on the barricade and decided to lighten the slide a little. Bobby at FGW did the mill work and Tri Topped and cut 3 lightening slots in the top of the slide. Cut it down to right at 10oz I believe he said. My old load was 4.8gr 231 under a 125 Missouri in 38 SC Starline brass which was very accurate and 100% reliable. After lightening, I tried it with the recoil spring I had in it(which I think was 8 or 9lb). Would not cycle. I put in a new 7lb spring and tried again. No dice. Ejected 1 of 7 rounds. Should I go on up on my load to get cycling back or go to a lighter spring. Common sense says a lighter slide would have dictated a heavier spring given the same load but this one did not work out that way. This is my first lightened slide( lightened this much) so I'm still in the learning curve.Did removing mass, which removed momentum cause the problem? What to do, what to do?

That would be my thoughts.

it may start a bit faster, but it loses energy quickly. This is an extreme example, but drop a brick on a spring, and drop a marble on a spring. Which compresses the spring more? What mainspring? If it will still fire, go to a lighter main spring. This helped my gun when i converted it to an open gun a lot.

Another thing, I wonder if the comp is too heavy, and its struggling to unlock with the lighter slide, so thats eating energy? Steel or alum comp?

Will it go to slidelock?

[Ed Robinson]

Slide was not refinished as it is stainless. I beadblasted it and reassembled. Comp is steel but it too was tritopped with the slide so it also got the diet treatment. The FP retainer is stock. I can recontour it but I don't think that is the fix.May help. Costs nothing to try. Mainspring is 17lb w/ 100% ignition. Upon firing. the slide will unlock and travel about1/2 to 3/4 inch rearward, simply closing on the fired brass it never ejected.I feel like the lower mass slide also has less momentum to continue on it's rearward path. Even the 7lb spring is overpowering it. I have 2 options for now, bump the load up to 5.0 or 5.2 grs to see if that will work or start cutting coils (which I really don't like doing) since we have a match this weekend and I probably can't get a lighter spring here in time.

[Action Pistolero]

Try what I suggested in your other post.

Another thing. Get some spare springs of different weights. They are cheap and you never know.

[JThompson]

Interested to know what it was when you get it figured out... it almost sounds like the gun isn't unlocking on time.

JT

Edited October 12, 2010 by JThompson

[GrantJ]

You may want to also try heavier springs as well. We had cycle problems with HelenJ's blaster when we fitted a lighter slide at the beginning of the year. The outcome was not good, we beat the locking lugs to death trying to find the problem. All indicators pointed to problems caused with lighter loads but in fact we were heading in the wrong direction. Kevin has it, springs are cheap, get a bunch of different weights and start heavy. Back them off a pound at a time until you get reliability.

GrantJ

[BPiatt]

None of this makes sense.... If the gun was functioning fine before you lightened the slide, it should be cycling even faster with a lighter slide.

You had better look for something slowing or catching on your new lightening cuts. Or maybe, if you took the ejector off, then it could be dragging on the bottom of the slide. Shoot it a little, disassemble slowing being careful not to wipe any dirt off. Look at the dirt marks, or more importantly, look for any shiny marks, indicating something is dragging. If the gun is plated and shiney already, you can make it black with a marker or some sight black. Barrel, slide and frame. Shoot a few rounds and look for any marks that would indicate dragging or catching.

I'd bet this is the best way to find your problem.

[Service Desk]

If the slide has been "pinched tight" in a milling vice rather than held in a slide jig for the machine work.... it could be dragging and slowing the slide down. I would do as Bruce suggests and then go back to the guy who did the work.

[Ed Robinson]

I'll do that Bruce but it feels so good as it's hand cycled, like grease on glass! Could be that Brian's Slide Glide is just too darn good. (Free plug there Brian) But seriously, I can't feel any bit of drag or anything. With the recoil spring out and assembled, muzzle up, it unlocks and falls all the way to the rear. Muzzle down, slide falls forward and locks right up. I'll do what Bruce recommended first (He is the Bianchi god anyway) then I'm gonna bump the load up to 5.2grs and see what happens. Honestly, when firing it, it just feels like the recoil impulse is just not enough to get the slide going. I guess when the slide was heavier, once it started moving, it wanted to stay moving and continued on it's rearward path. With the lowered mass now, it just doesn't have the momentum to carry rearward. Will post an update tonite or tomorrow a.m.

Thanks everyone for your help and tips.

Ed

[Ed Robinson]

I got it figured out today after a bit of head scratching. Loaded up 5.2gr 231 this morning and shot it---- with the same results!! I was really starting to wonder what was going on. I left it alone and thought hard about it for about 4 hours. One thing that I had overlooked, the gun was dry. No lube. Stainless slide, stainless frame, stainless barrel running dry. SS on SS galls! Took out my tube of slide glide and greased the rails, barrel lugs and cone, put 5 of the 5.2 loads in it and BAM BAM BAM BAM BAM just like new. Grabbed a handful of my old load (4.8gr) and it ate them up and spit them out like watermelon seeds. When I got the slide back from Freedom, I threw it into the blasting cabinet and gave it a glass shower then washed it down with MEK. I had also stripped and cleaned the frame with solvent and qtips to get the gunk and old grease out. When I got it back together I never did put any lube on it! Now I can get back to spring tuning as the slide velocity is definitely faster after being lightened. Thanks to everyone who chimed in offering suggestions. I was about to pull what little hair I have left out. Ed

(copied and pasted on the open gun forum)

[BPiatt]

One of my favorite saying is "you wouldn't run your car without oil.... why would you run your gun without oil. They're both metal machines"

FYI, grease on the rails will slow down the slide down and cause jams as well.... especially when the weather gets cold.