BoyGlock Posted July 1, 2014 Share Posted July 1, 2014 (edited) Load specs: 7.8gr 3n37, 10.2gr Z7. PF 170 for both. (IPSC) Head 125gr coated. COAL 1.25" primer WSP Nature of Jam in Z7: FTF. Wont chamber the last 1/4" or so about 20% of the time. In 3n37 in runs 100%. This is outside US. Im not sure whats Ziira7 equivalent in US. I really prefer Z7 because it feels much softer and flatter to me. But reliability is problematic. Any ideas how and why this is do? Thanks. Eta: rec. spring 7#. Tried 8#, same jam. Edited July 1, 2014 by BoyGlock Link to comment Share on other sites More sharing options...
DRichardson Posted July 1, 2014 Share Posted July 1, 2014 Never heard of z7 powder but is it a compressed charge? The OAL is sort of short for 9major. If it is compressed maybe inconsistant neck tension on the brass is allowing the bullet to be pushed out of the case by the compressed powder charge? Link to comment Share on other sites More sharing options...
BoyGlock Posted July 1, 2014 Author Share Posted July 1, 2014 Far from compressed. Lots of room for this powder in 38sc case. Think I can load as high as 11.5gr w/o it being compressed. Its a very fine and dense powder. 1.25" COAL is for 38sc. Wont fit 9 chambers. Link to comment Share on other sites More sharing options...
blind bat Posted July 1, 2014 Share Posted July 1, 2014 I've also never heard of Z7. It sounds like the round is loaded too long and the bullet is hitting the rifling in the barrel. I'd guess something on the press changed around the same time as the powder. Link to comment Share on other sites More sharing options...
BoyGlock Posted July 1, 2014 Author Share Posted July 1, 2014 I've also never heard of Z7. It sounds like the round is loaded too long and the bullet is hitting the rifling in the barrel. I'd guess something on the press changed around the same time as the powder. I go back to 3n37 anytime and shoot it w/o any jam so I dont think something changes averytime I use Z7, except the powder, of course Link to comment Share on other sites More sharing options...
BoyGlock Posted July 1, 2014 Author Share Posted July 1, 2014 You guys think 1.25" is too long? Ive used this COAL in my 2 2011s w/ 3n37 and n340 w/o any probs, and its been 2yrs now. I also know its within the max. L for 38s. And I usually caliper my COAL not w/ much frequency but enough to make me confident on my reloads. Link to comment Share on other sites More sharing options...
BoyGlock Posted July 1, 2014 Author Share Posted July 1, 2014 Ive seen this Z7 load run reliably in a friends gun, and also unreliably on another friend's gun. Jam is exactly the same as my FTF. This friend's gun that FTFs also runs reliably on 3n37 and n340. Btw, we have avery limited powder type for Open in my neck of woods. So far these 3 powders are the most common ones I know of, though n340 is a bit on the fast side. Sometimes I encounter some using 3n38 but its a rarity. Link to comment Share on other sites More sharing options...
Guy Neill Posted July 1, 2014 Share Posted July 1, 2014 Just to be clear, it is a failure to feed a loaded round, correct? I've seen instances similar where the fired case was left somewhat protruding as the extractor slipped over the case rim. If you are able to recover the rounds that do not fully chamber, do they chamber when tried later, with the barrel only (case gauge sort of test)? Not chambering such as you describe would seem to indicate some sizing problem since the cartridge is aligned with the chamber, if it has made it that far into the chamber. Either sizing of the case, or dirt/debris in the chamber would seem the main suspects. Guy Link to comment Share on other sites More sharing options...
BoyGlock Posted July 1, 2014 Author Share Posted July 1, 2014 The extractor does not slip. I inspected it myself. The rounds that FTFed would chamber when dropped into the chamber. I gage All rounds after each reload w/o fail. The shells are the same shells I load w/ 3n37 thats 100% reliable. When a round hangs in the chamber, a bit of forceful nudge would chamber it completely 90% of the time. This FTF happens even in clean chambers. And in both my 2011s. Im baffled by this for months now. Ive done a lot of tests on extractor tension, longer and shorter COAL, lower or higher powder loads, etc. and gave it a lot of thoughts to no avail. It always boiled down to this powder brand. But it works in other guns its why I keep on looking for the culprit aside from the powder w/c I dont believe to be so. It couldnt be my reloading technique as it also jams on a friends gun reloaded by another friend. And same type of FTF. Im deeply baffled and so I brought it here in Enos light. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted July 1, 2014 Share Posted July 1, 2014 Hello: Try loading to 1.230" OAL. Thanks, Eric Link to comment Share on other sites More sharing options...
Ace38super Posted July 1, 2014 Share Posted July 1, 2014 Try a 10# spring. If that solves the problem see if a 9# will work. The recoil impulse of that Z powder must be significantly less than 3N37. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted July 1, 2014 Share Posted July 1, 2014 Hello: I forgot to add what is the burn rate of the Z7 powder? Thanks, Eric Link to comment Share on other sites More sharing options...
BoyGlock Posted July 2, 2014 Author Share Posted July 2, 2014 (edited) Ive loaded it to 1.23" and also used 8# rec. spring in combi w/ different test loads. Same jam.I dont have any info on its burning rate. Its not in the net. I think its rebranded here in my place and have a different brand in the US. Im in the look out for powders w/ similar load specs in forum threads.I plan to load it to 175-180 pf. Goal is to push the slide back w/ more force and maybe help chamber the round w/ more authority. This should allow use of 9-10# springs as suggested.Appreciate all your feed backs. Edited July 2, 2014 by BoyGlock Link to comment Share on other sites More sharing options...
Ming the Merciless Posted July 2, 2014 Share Posted July 2, 2014 From your description and load data it sounds like it may be rebranded Accurate Arms #7. How many rounds fired before it starts jamming? Any unburnt powder in the chamber when it jams? Link to comment Share on other sites More sharing options...
BoyGlock Posted July 3, 2014 Author Share Posted July 3, 2014 (edited) W/ newly cleaned chamber, after about 20-25 rnds. It has unburned powder in the chamber area, but so has 3n37. Its just a bit more and finer than 3n37. If this is the cause of its jams why does it run volumes in other guns? On a side note, the cleanest powder Ive used in Open is n340. But isnt it a bit fast for comped guns? At 7gr. and 125gr heads PF 165, its good to go for IPSC but a bit bouncy for me, but very clean on the gun. The reason I mention this is, between 3n37 and Z7 I strongly prefer Z7, but if it wont be reliable in my guns, my option is limited between N340 and 3n37. Between this two, I slightly lean on n340 because of it being very clean-burning. Unburned powders in 3n37 and Z7 collect at the foot of sear spring. I see it everytime I detail strip my guns and if I have to put up w/ this, the powder must have a very defined advantage for me in terms of working my comps effeciently. This I see in Z7 vs 3n37. But not much in 3n37 vs n340. Eta: jam is more frequent than 20-25 rnds if chamber is dirty. Say at 10-15. Edited July 3, 2014 by BoyGlock Link to comment Share on other sites More sharing options...
Tino2212 Posted July 3, 2014 Share Posted July 3, 2014 Why don`t you try 3N38 or N350 ? Link to comment Share on other sites More sharing options...
BoyGlock Posted July 4, 2014 Author Share Posted July 4, 2014 Why don`t you try 3N38 or N350 ? These are not always available in store shelves. N340<N350<3n37<3n38 in burn rate as I understand, correct? Link to comment Share on other sites More sharing options...
Tino2212 Posted July 4, 2014 Share Posted July 4, 2014 That is correct but strangely N350 seems to generate more gas than 3n37 with lower loads . I load 7.6 grains of 3n37 in my 9 major and 7.1 grains of n350 and with n350 my gun seems to run flatter and softer i use 124 gr bullets . Link to comment Share on other sites More sharing options...
BoyGlock Posted July 5, 2014 Author Share Posted July 5, 2014 When I was just starting in Open w/ my 9 glock, I used up a 4-pound jug of n350. After that I couldnt find it anywhere here in my place. It was very clean-burning but a bit inconsistent to meter because its granules are bigger than usual. I couldnt say much about its recoil characteristics because I was just a noob in open then. I heard its the powder of choice by Eric G? Link to comment Share on other sites More sharing options...
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