Relationship between light springs, slide glide and crimp!

[GunslingerDK]

I just installed Hennings long firing pin, 13lbs hammer spring and a lighter recoil spring on my witness limited. Here's what I experienced.

Before installing these new parts I used the stock spring, I think it's 5.56kg which would be around 12lbs. I shoot lead bullets and therefore only crimp just enough to make the round chamber so as not to mash the bullet. These light-crimped cartridges are 100% reliable with the heavier spring, but I quickly found out the rounds would not chamber with the 6 and 8 lbs springs.

I loaded 100 rounds whiched I crimped some more. I get 100% ignition with the 8lbs spring but with the 6lbs spring only about 50%. And here's where it gets tricky. After adding slideglide to the slide, the lugs, the barrel and the guide rod, the gun started jamming. With the 6 lbs spring I could forget about it, the 8lbs was a little better but still jammed a few shots out of every 10. I removed the slide glide and the 8lbs worked like a charm again. It is the standard slide glide, and the temperature is around 40 degrees.

It's a pretty easy fix, I just have to crimp them further... and if I mash the bullets I will just have to make them harder.

I would like to know if anybody else have experienced this?? Any tricks or don'ts?? Did I add to much slide glide? Or does it have something to do with my mag springs? Gun is 5 years old and has somewhere between 25.000 and 35.000 shots through it.

[DownUnder]

Here's a quick test to help you problem-solve: Take the barrel out of the pistol. Give the chamber a good clean. Drop each loaded round into the chamber. In most chambers a round should drop in easily and make a nice clink. In a tight match chamber a round should still feed in easily. Give the round a slight press with your thumb then turn the barrel upside down. The round should drop out without much trouble. If it is a little long it might engage the lands a bit but should still come out without much effort. If the rounds are difficult to insert into the chamber or do not want to drop free then it is the ammo at fault, not the springs and slide glide.

[CHA-LEE]

GunslingerDK> Can you give us some more info on the ammo? What caliber? What is the OAL? Are you using a case gauge to check all of your rounds before you shoot them?

The slide spring shouldn’t make a difference in ignition of the rounds. The only time that can happen is if the slide isn't coming all the way forward to bring the chamber fully back into battery. How the base of the round is captured and retained by the extractor also makes a big difference. If you have sharp edges on breach face or extractor that cut into the brass as it chambers that will slow things down. This is easily tested by taking a round that has a new case and, lock the slide back and then drop the slide to chamber the round. Then rack the round out and closely inspect the head of the bullet and the base of the case and rim for any strange nicks or scrapes. These nicks and scrapes on the round are causes of excessive friction due to sharp edges. The only way to pin point these is to test rack rounds through the gun and inspect the brass/bullet for nicks/marks then deduce where the nicks/marks came from and polish up that area.

If you are using the 6lb or 8lb slide spring you need very minimal lubrication in the gun. You will probably need to use slide glide lite instead of standard and only a little bit at that. Especially if you are shooting in colder temps.

[GunslingerDK]

Sorry for the delay, had a busy weekend.

It is a 9mm. The COL is 1.140". The bullets are 130gr Round nose and 120gr Spitzer. Both lead and sized to .357.

Of course the slide has no effect on ignition, my bad... of course I meant that the slide doesn't close entirely. I increased the crimp on some rounds and tested them yesterday. With the 8lbs spring it cycles perfectly, but with the 6lbs I still get a few that doesn't close properly. Maybe increasing the crimp some more will help this??

No I do not test gage the rounds. However I do remove my barrel from the gun and put the round in. They only need a very fine push to go in completely. Are they supposed to go all the way in by them selves and fall out when turned upside down??

[CHA-LEE]

GunslingerDK> The rounds should fall in and drop out of the barrel with zero friction of binding. It sounds like you are using bellied brass and it is haning up in the chamber. This extra friction you are seeing in the chamber is what is causing your reliability issues with the 6lb spring.

[GunslingerDK]

I kinda figured. And yes I bell my brass, but only enough so as the lead bullets don't shear. I will have to make harder bullets and crimp them some more. Thanks for your help!