Was out testing some handloads in my 5.7 FN yesterday. Got two failures to fire. Primers showed very light primer strikes. Factory 40 gr. ammo worked as it has for about 300 rds. now, which is as usual. Loads were not still .2 grs. below top end and the brass and primers were otherwise fine.
Fired cases showed the case's shouder moved forward a good bit over factory brass..... Too much headspace ?
The gun hasn't been cleaned for the last couple of years. So I cleaned it up and played with everything. Seemed to work as it should, but... only time will tell.
I'm not happy with this. The gun is suppose to work even when dirty. The handloads used factory ammo with their bullets pulled and my charges of powder and the Sierra 40 gr. Hornet bullet. All the other handloads have worked fine, BTW. But, yesterday, I got two in a row that wouldn't fire. After that, six rounds of factory ammo fired normally.
Comments ? E
Hard to say what's up, but crud in the firing pin channel would be my first thought. I don't know the material used in the 5.7 FN, but it seems like the titanium and other lightweight firing pins need more attention than the good ol' steel ones.
E...I am sorry but you are kidding right. "Dirty" is one thing...has not been cleaned in a couple of YEARS is another...and it was handloads?
As to the misfires, it sounds like the die is setting the shoulder too far back...creating unacceptable headspace. If Wilson or someone else has one of the headspace gauges one may be a good investment.
And if it is running everytime with factory loads it is usually the reloaders problem not the guns or the manufacturer. Glock won't even certify their guns for reloads last I looked....
My apologies upfront if this is taken the wrong way...
Bob
I have not worked with a 5.7, but I agree that dirt, and possibly a bit of extra headspace as well, could cause the problems described. If the sizing die is set a little too far back, and dirt on the breechface is holding the case away from the primer, then light strikes seem more likely.
I appreciate everybody's feedback.
In my own defense for my laziness, I wanted to see how the gun would perform if not cleaned. It's suppose to run very well when dirty, has heavily phosphated internals, etc.
Well, I found out. After stripping, checking and cleaning the gun a good bit, several times, the main problem appeared to be powder residue on the bolt face and under/in the extractor. The bolt face was pretty dirty, and the extractor did have some hangups in it's travel before cleaning. The firing pin, it's travel, and magazine safety were not faulty from what I can tell.
Handloads and factory loads had the same position in the barrel which does have a generous chamber. The handloads were not full lenth sized and their shoulder lenths before firing were the same, etc. I assume that the gun is designed to have the large extrator hold the cartriage at the bolt face for it to recieve a good strike from the firing pin. With crud on the face, and, maybe, the extractor not getting a full bite on the case extractor cut of the case, could have done this. Odviously, the gun needs lots of testing to see if this is the case. So, for now, it doesn't get carried.
The only other area that might have contributed to this problem was the magazine safety. If the magazine isn't fully seated, the firing pin can't go all the way forward when the trigger is pulled - maybe. It was a hard to duplicate condition and i'm not sure it is possible, but, regardless, I see the day when that magazine safety gets removed along with a trigger job. E
does this round headspace on the tapered shoulder?
I would say no. The case shoulders on all loads, handloads and factory are all moved from .949 to about .985 inches after firing. E
E...
Been having a hard time with mine also. I have been doing this forever but this caliber has me stumped.
Failure to fire (your primer problem) separated cases at the shoulder (40 gr BT with 7gr of Blue dot. Quickload says not even close to max) and other problems.
All with handloads only. What a little bee-atch she is!
PS Quickload is totally unpredictable with the 5.7 I do not trust it at all!
It only failed to fire with two handloads. The next two were factory loads that did fire normally. I may have not seated the magazine properly with the handloads. The bolt face was pretty dirty and the extractor had some loss of smooth operation due to grit. Odviously it needs lots more testing at any rate.
I was very surprised to see how much the case shoulders were moved forward. I'm seriously considering not loading any even once fired brass. So far, all of my handloads have been factory ammo whose bullets I pulled so I could use the brass. But, with that much shoulder change, it has to seriously affect the brass strenth. At around 40,000-45,000 psi, with a loose chamber, I don't think I want to go there.
I've seen quick load fail miserably on several rifle loads. In a handgun, especially one as touchy as the 5.7, I wouldn't even consider using it. BTW, the hottest load I've used with Ramshot True Blue is 6.1 grs. with a 40 gr. short bullet, the Sierra Hornet bullet, not the longer V-Max styles. Both Ramshot and Accurate Arms warn users to be very careful working up loads at .1 of a grain increments and to be very carefull to follow the overall lenth specs. Both list different data for different lenth bullets of the same lenth.
I'm still a fan of the gun and the round, but I must admit it can be a bother. For instance, my maximum 40 gr. handload shoots about 3 inches higher at 15 yds. than do the factory loads. Good thing the gun has adjustable sights.
I'm going to try some loads with 45 gr. hornet bullets next. I'll post what I find. E
I would not even attempt to reload for such a cartridge. Just too small and TOO sensitive IMHO. Give me the chills just thinking about what a oops could do.
Yep. Especially in a handgun that's already known to go "KA-BOOM" with factory original loads.
E,
The fact that it was working with factory ammo, and had light primer strikes with yours, makes me think that your handloads had something about them that was preventing full chambering. Then when the firing pin hit the primer, rather than setting the cartridge off, it fully seated the cartridge. I would recommend taking a dial caliper and measure every aspect of the handloaded round to see if there are any dimensions that differ from a factory loaded round. You could be doing everything right, and it may be that your dies are not to spec; you never know.
Of course, this could also be a dirty chamber issue as well that is preventing the cartridge from fully seating.
Don't be ridiculous. The 5.7 FN is the perfect gun chambered for the perfect cartridge. It couldn't possibly ever go Kaboom.
hmmm...seems like a bit of dirt on the case could hang it up in chambering, and allow firing out of battery.
Sorry, VA but I don't buy that.
The loads, and they were handloads, were made from 55 gr. bullets, not the 40-45 gr. stuff listed on Ramshot's website as being tested as safe for that gun. Ramshot makes a strongly worded point that the cartriage is very sensitive to tiny changes in powder charges, bullet lenths and cartriage over lenth.
That right there is good enough for me. To give you an example, the starting load for a short 45 gr. hornet bullet is 5.4 grs. For a 45 gr. Sierra pointed bullet, the start load is 4.8 grs. So who knows just what this guy did. Did his heavy loads damage the gun ? He had fired a good many of them. They were, BTW, a charge of 5 grs of Ramshot True Blue with those 55 gr. bullets. Where did he get that data ? No loads for 55 gr. bullets are posted on Ramshot's website.
I've been handloading for a mere 54 yrs. I've seen lots of hot loads fired in both rifles and handguns. I've locked up bolts and blown a few primers on rifles. That's what happens when you don't follow loading data and proper loading techniques in a rifle. In a handgun, however, it's alot more serious. If you are lucky, you get a shaken loose handgun. If you aren't, it comes apart in the hand. That's because they don't have the design safety margins that rifles do.
His comment that the gun fired out of battery is just a guess.
I just got done retesting my gun. The rounds that previously failed to fire, fired perfectly this time. As did other handloads and factory ammo. Shot a nice 1 3/8ths inch graoup at 15 yds., BTW, with factory ammo. What was the problem ? I suspect dirt and powder residue preventing the extractor from holding the cartriages for the firing pin blow. I'm going to test more and see.
Like I said, the brass grows too much for me to consider reloading once fired brass. Any handloading I do will be with nothing but new, factory brass. But I do feel this round is worth reloading. The dramatic difference in penetration of hunting ammunition makes it worth it.
Another thing I've noticed is that for my gun to shoot the same sight settings as the factory 40 gr. V-Max loads, the load must be very close to it's velocity. At a little over 1900 fps., my latest loads land over three inches higher at 15 yds. Factory ammo clocks 1729 fps. in my gun. E