Misfires



  • I am having problems with misfires. The primers are from a lot I’ve been using with no issue. I coated some bullets in HBN for my 223 and was going to work the load back up for them. I have both Lapua and Lake City 16 brass. The Lapua gave me no trouble at all but the Lake City gave me 6 mid fires out of 15 rounds. I measured the primer pocket and the primer then gave it a .003 crush with my CPS just like I normally do. This is new never fired LC brass, and I’ve shot close to 500 pieces in a different 223 before with no issues. Any ideas?



  • Measure the headspace on the Lake City brass. Compare those unfired cases to fired cases.



  • @orkan

    Ok just measured them. Fired is 1.4425 most unfired is 1.440-1.439. I measured one the misfired and it’s 1.422. The rest of the mis fires after several trigger pulls finally shot.



  • I see what was wrong the brass was moving forward not letting the primer take the full force of the firing pin strike. I pulled the bullet and seated it with a jam and it fired. I’ve not had one single issue with any of this brass until now. Anything I can do to fix it besides jamming the billets?



  • @bull81 said:

    I see what was wrong the brass was moving forward not letting the primer take the full force of the firing pin strike. I pulled the bullet and seated it with a jam and it fired. I’ve not had one single issue with any of this brass until now. Anything I can do to fix it besides jamming the billets?

    Bingo. This is one logical effect of short headspace on a cartridge.

    The rounds that actually fired, that had short headspace, will likely have case head separation in their future, if they were fired with 20 thousandths of headspace as you indicated, in a bolt with a spring loaded ejector. Even in something without a spring loaded ejector, the case will often be thrown forward as far as the extractor will let it go due to momentum during chambering.

    Seating the bullet out into the lands, or creating a false shoulder on the neck are the only methods I'm aware of for keeping the case head against the bolt face and allowing proper brass growth at the front of the case.



  • @orkan

    Thanks, I don’t know if the ones that eventually fired had that much headspace but the one that never would fire certainly did. I just measured about 25 and the all fell in the 1.439 to 1.441 range but two. Those two were 1.437 and 1.438. Any guesstimation on what the limit would be for firing correctly? I’ll sort them out and jam the ones that fall short by X? amount. I mainly wanted to load these for positional practice so I wouldn’t loose my Lapua stuff.



  • @bull81 said:

    Any guesstimation on what the limit would be for firing correctly?

    Depends on the rifle. Even with 40-60 thousandths of firing pin protrusion, the inertia of the cartridge moving will rob a lot of energy and will create problems. In the event of an AR, going to a super heavy duty hammer spring can alleviate a lot of ignition issues. Though if you only have 40 thousandths of pin protrusion, and you lose 25 thousandths to headspace... all the strength of impact in the world won't make a difference, because the pin won't get into the primer deep enough to give solid ignition.

    My question is how did you end up with brass that has over 20 thousandths of headspace variance? Secondarily, I think most shooters would have less problems if they were to batch test and inspect their components before they load them. With brass, I check its dimensions and tolerance among the lot number before I set out to work with it. Saves me from potential issues later. Knowing of this headspace issue ahead of time would allow for proper fire forming, for instance. :)



  • @orkan

    I have about 1200 pieces of this brass I bought new never fired. I originally bought it for an AR and have 300 pieces that stay with that rifle, they are on there 3rd firing now. Then I had 200 pieces I used in a ruger precision rifle chambered in 223. I’ve been using the Lapua brass in this 223 which is the TL3 from travis. I just got the remaining unfired LC brass out for practice rounds and ran into this issue. This is the first time I’ve had a single problem out of it with misfires. I do check all my brass for match stuff but never have on practice ammo like this. I would never thought I’d need to check headspace on all 1200 pieces before loading them. I’ll measure through and sort the remaining brass and jam anything below 1.438 for the first firing.



  • @bull81 said:

    I would never thought I’d need to check headspace on all 1200 pieces before loading them.

    I definitely don't check every piece, but I spot check 20-50 pieces of new lot numbers of brass.

    I've come into the habit of fire forming all first firings on my brass.



  • Ok still having problems with misfires. I just loaded up 18 rounds and 9 misfired on the first try and 8 of them fired on the second. One flat out won’t fire. I measured headspace on all 18 cases and all 18 were 1.440 or 1.4405. This is only occurring with the LC brass the same primers in the Lapua brass work fine.



  • And this just got really strange. I just took the one bullet that wouldn’t fire apart and measured headspace on it again because the bullet was jammed deep inside the case after trying to fire it multiple times. The headspace now measures 1.420. I checked all them prior to firing to insure they were all 1.440 to 1.4405. This is the same thing that happened yesterday I now realize the headspace didn’t start out that far out yesterday either. @orkan any ideas



  • Ok, I'll have to just throw possibilities at you here. Could be lots of things at this point.

    Are you jammed so deep and so hard in the case that when camming over you're changing the shoulder angle on the brass?

    Did you mention you installed your own trigger? Are you certain that the sear in the trigger you installed isn't putting too much force on the cocking piece, causing excessive firing pin drag or bolt tilt?

    What primers are you using? If running a hard cup primer and also having pin drag, you might not have the "punch" to ignite reliably.

    What depth are you seating primers to? Are you sure they are in the bottom of the pocket? If you're jamming the bullets as you describe, then the base should be pressed against the bolt face, but if you aren't seating them deep enough and the cup is hard, the primer will scoot forward in the pocket, robbing inertia and subsequently the firing pin will shove the case forward too.



  • @orkan

    I did not jam these rounds, they are jumping .010. I was only going to jam the ones that were bad out but at this point I don’t think the headspace is the issue. I did install my own trigger and it seems to be working fine, but truth be told I can’t swear by that. I am using CCI-450 primers and have already thought about the hard cups so I am going to load up some BR-4’s to try. That’s all I have on hand at the moment.

    I took a piece of fired brass that still had the primer in it and chambered it. I dry fired it 8 times and pulled the brass out and measured headspace it had shrunk .016 from its fired size. So I think that’s the reason for the headspace issue. I never would have thought the firing pin was hitting hard enough to set the shoulder back that much. Which brings me to this idea. Is it possible with the hard cups on the 450’s that this brass is a touch soft to start with and when the firing pin hits the primer the brass is setting back enough that the round doesn’t fire?



  • @bull81 said in Misfires:

    Is it possible with the hard cups on the 450’s that this brass is a touch soft to start with and when the firing pin hits the primer the brass is setting back enough that the round doesn’t fire?

    Boy that's a tough prospect. I just can't see one hit from the firing pin setting it back far enough to matter. Repeated firings on soft enough brass... sure, it's not unfathomable that it would set it back a thousandth or two at a time... but that by itself shouldn't steal enough inertia to stall it out on the firing unless initial headspace is also too short.

    As you said this doesn't happen with lapua, its certainly something specific to this brass.

    What about the primer depth I asked about? You sure you're getting them seated to the bottom in the lake city? You could always try to go with full anvil compression and see what happens.



  • @orkan

    Yes sorry the primers have a .003 crush and I use the CPS so I know they are consistent. I measure the pocket depth then measure the primer thickness to come up with my seating depth. Correct same primers have no problem in the Lapua brass, only the LC brass. I know the idea of the firing pin setting the brass back enough during firing would be a long shot but I was just reaching for ideas at this point. Fired brass measured 1.442 and all this brass measured 1.440 prior to firing, so I could be wrong but that doesn’t sound like an issue in itself. I’ll try the BR-4 primers tomorrow and see if they make a difference, I’ll also check the headspace on amy that don’t fire on the first try and see if there has been any changes.



  • @bull81 said in Misfires:

    I’ll also check the headspace on amy that don’t fire on the first try and see if there has been any changes.

    I have seen, and do know that brass can get set back by the firing pin. ... but only a thou or two at a time. There's not much area up on a 223 shoulder, so it's not impossible and I have seen it. I just can't see it being the root cause of this.



  • @orkan

    I’ll give what we discussed a try tomorrow and update the thread with my results. Thanks for your help and as always enjoyed the conversation.



  • @bull81 Happy to do it. I look forward to your results.



  • @orkan
    Ok fired one piece of brass with just a primer seated no powder or bullet. I used the BR-4’s for this test since I had already seated them last night. The primer did go off on the first trigger pull, and I did not drop the hammer on this one more than once. Below are the results.

    Before firing

    sommAky.jpg

    After firing

    OAGChBz.jpg



  • @bull81 said in Misfires:

    @orkan
    Ok fired one piece of brass with just a primer seated no powder or bullet. I used the BR-4’s for this test since I had already seated them last night. The primer did go off on the first trigger pull, and I did not drop the hammer on this one more than once. Below are the results.

    Before firing

    sommAky.jpg

    After firing

    OAGChBz.jpg

    What in the world?!
    BigHorn's really don't even hit the primer that hard. They are set up for only .220" fp travel with a long sear trigger like a Jewell. (.240-.250 is standard)
    That brass must be incredibly soft. Granted a straight 223 has a pretty small frontal area of shoulder with a pretty good slope, but still, I can't believe it's moving that much.
    Zero issues with Lapua, correct? Have you tried any other brands of brass?



  • @tscustoms
    I know beats all I ever seen. Zero issues with Lapua firing. I have a few pieces of federal some hornady I can try to see if it has any problems. I’ll also do the same test on a piece of Lapua when I get back home.



  • I'm very interested in the lapua test. I've seen setback on dry fire before... but nothing like that.



  • @orkan

    I’ll be off today after lunch and will see what the Lapua does. I have 200 pieces of it with 450’s already seated but not loaded. I’ll keep you posted.



  • Ok just ran the primer test on the Lapua brass. Looks like this LC 16 brass is ridiculously soft. @tackyp didnt you do a load work up with some LC 16 brass? If so have you noticed it being extremely soft? I’ve used it in several other rifles without issue. My thought is the spring loaded ejector on most other actions is forcing the brass into the shoulder area of the chamber tightly so there isn’t any movement. With the bighorn there is no springloaded ejector so when the firing pin hits the primer the brass slams forward into the chamber building momentum as it goes crushing the soft brass and absorbing the impact of the firing pin causing misfires. @orkan what are your thoughts on this?

    Before firing

    IwTcdz1.jpg

    After firing

    V7zZnkI.jpg



  • Yup, that's the kind of setback I'd expect and have seen many times.

    That lake city brass must be ridiculously soft. That's really the only explanation that's left. Measure the rim thickness on it vs the lapua. Could be the thick lapua rim being held back a bit by the extractor... but that's my last guess.

    Were that brass mine, I'd reserve it for use in an AR and let it spit em on the ground and leave em lay.

    Also, I'm docking you fake internet points because you are forcing every human being to cock their head left and right to see your pictures. lol You sir, have disrupted the necks of all those on the hive!



  • @orkan

    Ok just measured the rim, not the easiest thing to measure but I came up with .042 for the Lapua and .043 for the LC.

    I may skip annealing and try to size some of the fired LC brass and see if it work hardened enough to reduce the set back just in the name of science. I’m done trying to make it work in this rifle at this point though.



  • @orkan said in Misfires:

    Also, I'm docking you fake internet points because you are forcing every human being to cock their head left and right to see your pictures. lol You sir, have disrupted the necks of all those on the hive!

    Haha my apologies on the jacked up picture angles



  • @bull81 said in Misfires:

    @tackyp didnt you do a load work up with some LC 16 brass? If so have you noticed it being extremely soft?

    I did and I haven’t, but mine was all factory loaded and once fired from my (and others) AR15s.



  • Just sized two fired pieces of LC and did the primer test again. It set both pieces back .002. Apparently skipping the annealing process for 1 or 2 firings would probably get it useable if you really wanted to go to that much trouble. Not sure if it would stay that way though if you ever annealed it.



  • Thanks for the science. :)



  • Loaded 17 of the LC 16 brass with BR-4 primers a while back when I was having the misfire issue. I forgot about them and saw them last night. I decided to load them up and see if the BR-4’s helped any. Just finished shooting them and didn’t have a single misfire so I guess the softer cup on the BR-4’s eliminated the crushing affect the 450’s we’re creating.

    Still probably won’t bother fooling with this brass anymore except for maybe some AR stuff but figured I’d share what I found.



  • Having setup and cleaned about a million head turn machines in my time....
    You will see a couple thou variation in rim thickness and that is when everything is going well. Collet tightness, lube, web thickness, etc all can impact it. Oh, and if not cleaned every few hours, that is bad.
    Even with primer pockets cut to uniform depth, this is one reason seating by feel could be argued for. But obviously great results can be had with fixed depth seating in a shellplate, especially when working with tighter tolerance components.
    Ammunition is a fascinating study in tolerances.



  • @prometheus

    Well the problem with this brass is it’s too soft. It took some time but we were able to figure out the cause. Greg had a good idea of loading a primer but not powder or bullet, when I fired it and checked headspace the headspace had shrunk by a very significant amount. I can’t remember off the top of my head how much now but it was drastic. Basically the shoulder was crushing enough to rob enough momentum from the firing pin that it wasn’t going off. I normally use CCI-450’s, the BR-4’s have thinner cups and don’t have the same issue.



  • Did I just flunk junior high math here? Your pictures show five ten thousandths reduction in headspace, assuming that your caliper is accurate to the last displayed digit. Firing pin protrusion is what? 35-50 thousandths or 350 - 500 ten thousandths? I'd be checking firing pin protrusion and firing pin spring tension. 1-2% reduction in the depth of indention should be of no noticeable consequence. Just my 2 cents worth.



  • @rr2241tx said in Misfires:

    Your pictures show five ten thousandths reduction in headspace, assuming that your caliper is accurate to the last displayed digit.

    Look at the previous page please. Hell of a lot more than 5 ten thousandths movement. The above example on this page was recorded setback from GOOD brass, where the previous page was setback from poor brass.



  • @orkan You're right. Reading the forum mostly on the cell these days and did not get far enough back to see the previous pair of photos. The bad ones seem to show 5.5 thousandths reduction in headspace. Doesn't appear to be a weak firing pin spring. I don't shoot that much high precision bottlenecked brass but if the shoulder is deforming that much it certainly could rob enough impact energy to have a variable effect on hard cupped primers. With rimmed straight case rifle brass I have seen misfires when the primers were seated flush rather than with a slight crush, especially if the reloader was using large pistol primers rather than large rifle primers. Hard cupped pistol primers can be driven home in a rifle depth pocket and not indented enough to set off the priming compound reliably.


 

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