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9/19/2017 7:27:10 PM
Posted: 3/8/2006 5:35:27 PM EDT
Extracts but will not feed or lock open. Did all the short stroking checks, and then switched to overpressure after finding long case gouges and corresponding marks on the rims. While not maximum published loads, this is a tight match chamber ( fired necks measure .254 ) and flat primers with velocities near max lead me to believe these were a little hot. However, how can this be an over pressure failure with the regulator set to minimum gas? Also failed to feed at maximum gas. So I must be short stroking and the case marks are not an overpressure sign. I'm stumped.
Any suggestions would be appreciated.
Link Posted: 3/8/2006 9:13:49 PM EDT
Link Posted: 3/9/2006 5:41:46 AM EDT
Thanks Dano. Will load up some reduced rounds.
Link Posted: 3/9/2006 8:27:39 AM EDT
[Last Edit: 3/9/2006 8:38:36 AM EDT by leftyshooter]
Before I head to the range with the reduced loads please consider my loading info for over pressure. After studying the numbers, they seem within reason to me. 24" barrel: 53 gr matchking with 25 gr of H335. Book says 3100 for 25.5 gr of powder. Actual velocity was 3160. Another load : 69 gr matchking with 23 gr of H335. Book says 2700 for 23 gr or 2867 for 23.5 gr of powder. Actual velocity 2885. While the Dpms BCG passes the 40 degree drop test dry. With a little CLP it does not quite make it. The Young BCG does not pass. Could tight lugs be a contributing factor? I should add that I've tried the original buffer (collapsible stock) and a hydraulic buffer which I questioned as a source of possible short stroking because it required considerable effort to manually lock back the bolt. Would not this buffer help with an overpressure situation?
Link Posted: 3/9/2006 3:44:14 PM EDT
[Last Edit: 3/9/2006 3:46:49 PM EDT by Dano523]
Link Posted: 3/9/2006 6:12:14 PM EDT
From your explanation the dpms is ok, the Young needs a little work. I've got reduced loads ready to go tomorrow. Will report.
Link Posted: 3/10/2006 2:06:33 PM EDT
Shot reduced loads from 25 to 23 then 22 of h335 for a 52 gr matchking. These loads don't even extract. Removed gas block. Found a little mis allignment. Opened gas block hole to better match.
Measured barrel hole of .093. Reshot some 25 gr loads. It cycled properly a few times but mostly failed to feed and hold open on an empty. Pretty much as before.
Link Posted: 3/10/2006 5:28:25 PM EDT
[Last Edit: 3/10/2006 5:34:12 PM EDT by Dano523]
Link Posted: 3/11/2006 4:52:36 PM EDT
Originally Posted By Dano523:
Give me the specs on the barrel,
including chamber ream (cal, including headspace spec) throat length to engaugment from end of chamber cut, barrel length, gas port size, and do confirm that the chamber has been finaled reamed correctly and polished (read no grooving from the reamer).

O.K. hear goes. New Krieger 24". .223 Rem JGS 0514 HEF ( This reamer drawing is currently on another thread about short stroking). I do not understand "the throat length to engagement from end of chamber cut" dimension, but I'm sure it's on the drawing. Gas port size is .093. The chamber appears highly polished, but I don't have a magnifying bore scope. Being a Krieger I'd like to assume it's reamed correctly and polished. They freely admit to reamer marks in the throat as the sole reason to do a shoot and clean break in.

The chamber drawing indicates 1.4636 min headspace. No max is given but length tolerances are held to .005.
The zero on my RCBS precision mic is also 1.4636. The measured headspace was determined with extractor and ejector removed from both bolts using cases measured very carefully in the precision mic.
The DPMS bolt closes up to 1.4606 and will not close at 1.4616.
The Young bolt closes up to 1.4646 and will not close at 1.4656.
The reduced load primers look fine. The first shot primers just looked a little flat. I've seen a whole lot flatter.
Link Posted: 3/11/2006 6:01:40 PM EDT
Link Posted: 3/12/2006 5:36:58 AM EDT
Don't believe there are any round binding issues. Loads were set .010 off the lands using a Stoney
Point. Neck diameter was .250 then .254 fired, drawing has .25489. Neck tension was .001 then .002 using Redding bushings.

The Krieger gas block is extremely , ridiculously tight to the barrel and tight to the tube. It concerned me during both installations (regiggered block port to barrel port. It pushed the tube toward the receiver. I used a screwdriver to lever against the tube regulator to reposition the tube to align the roll pin. This seemed like way to much stress on the tube, so I have already ordered a new standard tube. I will now have to tap on the receiver end of the tube to align the roll pin.

I've been through the buffer and spring a few times. While I could not see how it would bind the buffer roll pin does protrude and will be ground down.

It's not really a FrankinGun. RRA upper and lower with RRA 2 stage. Gas buster CH. The regulator, hydraulic buffer (currently on the shelf) and collapsible stock were an attempt to build the gun for young kids to enjoy, and me to target shoot. An A2 is on order for me. The collapsible
doesn't work off of a bag.

I'll shoot it with the new tube ........and stock and go from there.
Many thanks for your efforts.
Link Posted: 3/13/2006 4:27:37 PM EDT
While waiting for parts, shot 20 rounds of Wally World Rem. and had Zero extractions. Read other thread on FTF and saw info on springs so I measured mine. RRA 6 pos. collapsible has a 11.25" spring. Isn't this supposed to be 10"? While this came from a reputable dealer, I wonder about the buffer as well. This is 3.26"
Link Posted: 3/13/2006 7:45:33 PM EDT
Link Posted: 3/14/2006 5:32:40 AM EDT
No joy is right. I've got a super accurate .....single shot! At least I don't have to chase down my brass. The bolt locks up fine on the drop test. Works flawlessly manually. It does require some effort to lock it back. Guessing here. maybe 15? pounds. Sure seems like a gas leak.

I disassembled the gas system again. I had previously adjusted the block to tube opening. This time I indexed the gas tube to the free float tube with the roll pin in the block, removed the block and using the marks saw where the gas tube port and the barrel port were not totally aligned. Enlarged the tube port, and shot the factory stuff to no avail. Checked the gas tube for clearance thru the barrel nut and checked the fit with the carrier.

I've been thru the bolt. Rings staggered. Tight fit into the carrier.

The Young BCG did not come with a bumper in the extractor spring. Would this account for the case marks?

I am unable to move the key bolts. Don't know how to check for a leak in the key. There was some fouling along both edges of the key. What are the chances of two new BCG's having a key leak?

Waiting now on new tube and block. This one has been thru the wringer.
Link Posted: 3/14/2006 7:19:20 AM EDT
Link Posted: 3/14/2006 1:35:43 PM EDT
Not binding at the bolt and no added resistance felt at cocking point. Just requires some effort and the last part is harder. I originally had a hydraulic buffer. It was all I could do to manually lock the bolt, so it came out immediately after the first failure to lock. I guess the A2 which will be on shortly will help sort the spring issue out...........assuming it comes with the correct spring/buffer.
Thanks again Dano.
Link Posted: 3/16/2006 11:52:14 AM EDT
In my original post I mentioned badly marked up cases. Well, I've been reading the magazine thread................and take a wild guess what my D&H mags are stamped. I'll give you 10 guesses and the first 9 don't count. Yep, 11/05.
Link Posted: 3/21/2006 4:26:15 PM EDT
Latest Update. Latest theory was tight spring. Well that didn't pan out. Put an A2 stock with its spring and buffer. Twenty rounds; same result ; failed to eject. So I replaced the regulated gas tube and checked the flow and replaced the Krieger block ( which was rediculously tight ). Checked the key again (after another 50 rounds) and found a loose bolt. The staking looked suspicious so I removed the key, placed lock tight on the flat and rebolted with good staking. My guess is it will still not function. I am probably wrong, but I wonder if the bolt isn't sticking. It passes the drop test, even locks up on most drops, but this is without a case in the chamber. I've noticed no hesitation in pulling the bolt back without a round in the chamber. With a round in the chamber it requires more effort to get it to unlock. This is no different for cases of differing headspace.
Link Posted: 3/22/2006 10:09:06 AM EDT
Link Posted: 3/22/2006 11:21:34 AM EDT
Oh man that sucks. Please take it easy on the food when you start to feel better. It can flare up again with the wrong fuel. Don't have to worry about me anymore. Just returned from the range. All is well with the world. Ran like a top. It was short stroking from probably a combination of tube, block, and key problems. The case marks were from D+H batch 11/05 mags. Thanks for all your suggestions.
Link Posted: 3/22/2006 12:54:46 PM EDT
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