My testing on csspecs prototype

[kmoore 3]

Got mine out to the range over the weekend. Short version, I had failures to feed and failures to extract. I had planned to snip a coil off of the spring, but felt that the spring wasn't the issue so I decided to wait on that. It's already pretty short and the mag doesn't seem oversprung to me. Thinking about it later, I'll try putting in a spring from a factory mag to see if that helps.

 

Shotgun description:

My shotgun is unconverted. It has been pretty reliable, but I don't shoot it nearly as much as my (competition) S12.

 

Ammo used:

I took a can of shells I thought were standard to the range ... but upon opening it up I'd grabbed a can of 1 oz heavy field loads (standard load is 7/8 oz). I doubt this is the cause, and a mag should handle this anyways. These were 2 3/4 shells. I did all of my shooting with these.

 

 

Shooting details:

I ran a 5 round mag thru first, ran flawless. I did this to confirm the shotgun is running as I'd expect. I paid particular attention (in the whole range session) to firmly shouldering the shotgun .... it's been my experience during shotgun matches that a weak shoulder (caused by an odd shooting position or shooting on the move) can cause some misfeeds. I'm confident I took that wasn't a cause of the problems.

 

First try with test mag:

Shell number 2 and 4, failure to extract. Pics below.

 

Second time with Mag:

2 failures to feed ... shell was partway loaded into the chamber and the remedy was a slight bump on the handle. They didn't catch any of the chamber, just didn't seem to have enough energy to get into battery (i.e. they didn't nose down and didn't catch on the hood of the chamber) Last shell did the same thing. I fired that final shell and it did not clear the shotgun, it stovepiped. This is a failure to extract, but if this was the only problem I wouldn't care much as it automatically clears with a mag change.

 

Third time with Test Mag:

On the last magful (third mag), I had my son take high speed video of me. Props to him, he was hit by most of the empties but stayed with it! It's painful to watch (~9 minutes of video to watch one mag and a couple of jam clears!) But it MIGHT help in diagnosing the issue? oops, the summary is I had a failure to feed on the first round, and a failure to eject on the next to last round.

 

Factory 5 round mag:

No issues again. Son Shot this with high speed again. But I did notice the factory mag always seems to barely get the shell out ... almost failing to eject ... on a couple of rounds.

Edited June 9, 2010 by kmoore

[kmoore 3]

first of two stovepipes on the first use of the test mag.

Edited June 9, 2010 by kmoore

[kmoore 3]

Second of the stovepipes

Edited June 9, 2010 by kmoore

[kmoore 3]

one of several failure to feed:

Edited June 9, 2010 by kmoore

[geepelton 105]

nevermined

Edited June 9, 2010 by Rangerguy

[csspecs 1,987]

I'm thinking that the follower needs to be longer and smoother. What is likely happening is the follower is binding into the magazine body and robbing power from the bolt (which is borderline already).

 

I'd love to see the high speed videos.

 

Thanks

Mike

[kmoore 3]

The videos are up on youtube. As an FYI, I imported the movies into movie maker ... got rid of footage before the first and after the last, and other "dead" spots.

video was shot with my new camera, it's a casio exilim. Was set to shoot 1000 fps, which narrows the field of view pretty tight. There are a couple of other "slower" captures that give a larger picture, but all I cared about was the action of the bolt.

 

5 round factory mag at

 

8 round prototype mag at

 

Let me know if those links don't work.

Edited June 9, 2010 by kmoore

[garandman 11]

kmoore -

 

Seriously awesome work. You obviously took your beta tester duties seriously - thank you.

 

Tell me about your gun. Any of the usual functionality upgrades to make it run better? (twiter puck, Gunfixr gas plug, lighter front op rod spring, lighter hammer spring, open up the ports slighty (how many ports?) re-shape the opening in the gas block to make sure ports are unobstructed, etc)

 

As you noted, even the factory mag barely clears some of the spent shells. Granted, its the same gun with both mags, but I'm curious if your gun is 100% factory.

 

My diagnosis -

 

1. FTF: the mag body is too low in the gun, or the follower was binding for that one round and created too steep an angle to feed. (Often the problem here is a WEAK spring, or de-horning the follower so it doesnt bind. A plastic follower would be difficult to make, but prolly feed better.

 

2. FTE: ejection seems marginal with your gun, generally, and with both mags. As a rule, I'm looking for shells to eject at least 7 feet from where I stand. How far does you gun throw shells?

 

Again, thanx for a killer write up, pics and vids. You done csspecs a real service. Thanx to your son for the vid - great work keeping the gun centered in the frame, even during recoil.

[SaigaNoobie 66]

I'd like to note (Purely non-mag related) that the shells that almost or did FTE, seemed to bounce off the dust cover and the rims bounced off the op-rod and back down into the gun... I'm curious to see what I can do to enhance the function of my 20ga when I get it converted.

 

Look at 1:05 in 5rd mag vid vs 3:30 in CSS mag vid. The round moves the same way, just by random chaos, catches on the 10rd and doesnt catch on the 5rd. It's almost as if the extractor is too low in the receiver and causing the shell to extract UPward instead of to the right.

 

I love Slow-Mo.

Edited June 9, 2010 by SaigaNoobie

[SaigaNoobie 66]

By the way, $275 for a 1000fps digital camera? SHIT! I may just buy me one for the Slow-mo capabilities!

[kmoore 3]

kmoore -

 

Seriously awesome work. You obviously took your beta tester duties seriously - thank you.

 

Tell me about your gun. Any of the usual functionality upgrades to make it run better? (twiter puck, Gunfixr gas plug, lighter front op rod spring, lighter hammer spring, open up the ports slighty (how many ports?) re-shape the opening in the gas block to make sure ports are unobstructed, etc)

 

As you noted, even the factory mag barely clears some of the spent shells. Granted, its the same gun with both mags, but I'm curious if your gun is 100% factory.

 

My diagnosis -

 

1. FTF: the mag body is too low in the gun, or the follower was binding for that one round and created too steep an angle to feed. (Often the problem here is a WEAK spring, or de-horning the follower so it doesnt bind. A plastic follower would be difficult to make, but prolly feed better.

 

2. FTE: ejection seems marginal with your gun, generally, and with both mags. As a rule, I'm looking for shells to eject at least 7 feet from where I stand. How far does you gun throw shells?

 

Again, thanx for a killer write up, pics and vids. You done csspecs a real service. Thanx to your son for the vid - great work keeping the gun centered in the frame, even during recoil.

 

Thx. I bought the gun second hand a couple of years ago. Friend of a friend had it, he had ~100 rounds thru it. I like "tactical shooting" matches and mostly use the S12 but if the right gear was created (such as hi cap mags) the 20 can be very effective. So I've mostly held onto it. Doubt I have put more than 300-400 rounds thru it, all sporadically. It's stock, I haven't even polished the bolt/hammer interface or anything else internal. Next time I pull the gas plug I'll notice the ports, but I really don't know. I did wedge the bolt fully open for a month or so, to compress the springs a bit ... basically a cheaper way to break it in (I think). I had a S20 originally that I sold to buy my S12 ... dumbest move ever. That S20 was stone cold reliable. This sample is a bit less so, tho I think it's getting better. Hadn't really payed attention to how far the empties fly, but thinking back on picking them up after that session, I'd guess 3-4 yards over and a yard forward is where most had landed?

 

 

 

 

By the way, $275 for a 1000fps digital camera? SHIT! I may just buy me one for the Slow-mo capabilities!

 

if you are patient, you can catch it cheaper... I visit www.slickdeals.net and just watch their "front page" forum area... IIRC it's sold for $210 the last two times it was reported on sale. It's fun to mess with. It's got a huge zoom and another feature that I think I'll like .... it'll take a whole series of photo's with a single press of the button ... then you can go thru and find the one where everyone smiles and has their eye's open .... . So far I'm a fan

[kmoore 3]

I'd like to note (Purely non-mag related) that the shells that almost or did FTE, seemed to bounce off the dust cover and the rims bounced off the op-rod and back down into the gun... I'm curious to see what I can do to enhance the function of my 20ga when I get it converted.

 

Look at 1:05 in 5rd mag vid vs 3:30 in CSS mag vid. The round moves the same way, just by random chaos, catches on the 10rd and doesnt catch on the 5rd. It's almost as if the extractor is too low in the receiver and causing the shell to extract UPward instead of to the right.

 

I love Slow-Mo.

 

Good eyes! you are right, the shell path is almost identical ... the factory mag barely makes it out!

 

If I had lots of money .. I'd shoot up 300-400 rounds thru each and get a better estimation of the failure rate in the two mags!

[garandman 11]

I've found my S20 gets more and more reliable the more I shoot it - prolly 200+ rds thru it thus far.

 

I suspect the same is true for mags. We won't really get a full sense of reliability until we get at least 200 runds thru it.

Edited June 10, 2010 by garandman

[wired 27]

I have a casio exilim and I had no idea it does that stuff. Time to play.