Powder residue on cases bad
- Thread starter Matt_3479
- Start date
Minimum trim length is 1.900" (SAAMI) Max is 1.920"
Check neck tension before & after bullet seating. Has the necks outside diameter increased by .002" or more, after bullet seating? This produces about 35 lbs minimum bullet pull. (Minimum 5.56 military standard.)
This is not low pressure. Hodgdon lists it near maximum.
Check neck tension before & after bullet seating. Has the necks outside diameter increased by .002" or more, after bullet seating? This produces about 35 lbs minimum bullet pull. (Minimum 5.56 military standard.)
I have had this issue with my 6 creed, what I found was that there was carbon deposits in the chamber
neck area causing the case neck not to seal properly.
Check the neck area for carbon and clean if you find carbon.
neck area causing the case neck not to seal properly.
Check the neck area for carbon and clean if you find carbon.
i did have this on my 6 creed at around 300 round range. I got a ring. Verified by pressure spike and bore scope. Removed it and pressure and node returned and gun starting shooting again but the soot Is now bothering me like crazy.
I will check everything here shortly. I should be home in a few moments
so I double check. It’s not length. Cases are 1.910”
I double checked neck tension. Loaded bullet is .269-.2695 and a sized case is .2675-.268. So roughly .0015 thou neck tension
dellet
Gold $$ Contributor
You might check neck diameter of both the chamber and fired case. Hopefully it’s not an issue of too large of a chamber. If you have brass with a thicker neck you might give it a try.
A quick and reasonably accurate way to measure without casting the chamber is to expand the lip of the neck until it drags like you would for a cast bullet, until you can feel it drag on the chamber. Then measure.
A quick and reasonably accurate way to measure without casting the chamber is to expand the lip of the neck until it drags like you would for a cast bullet, until you can feel it drag on the chamber. Then measure.
Coyotefurharvester
Silver $$ Contributor
You gave some fired case measurements, but you didn't tell us how much headspace. Only told us you are bumping the shoulders back 0.0015+. Do your fired cases shoulders need to be moved because the case chambers hard?
how do i accurately expand the lip of the neck gradually to measure the chamber?
Im running cci 450 primers
I can’t run suppressors in Canada unfortunately so it’s not that.
I went back through my notes and it looks like fired case dimensions are 1.532” and I’m bumping back to 1.5305”. I’ve always bumped shoulders back .001-.002 thou as that’s how I was taught and gives a little room for conditions. This particular rifle sees a lot of field use and didn’t want 0 head space and cause an issue
dellet
Gold $$ Contributor
You can use a mandrel or sizing die for a larger caliber if you have one, you just touch the neck enough to open it. A larger caliber bullet pressed into the neck. A lot of people use a tapered punch. Inserting the flaired case in the chamber will essentially reduce the diameter to chamber size. It’s rough, but can be done with what’s on and.
It’s a throw back to a different type of loading, where the bullet is seated ahead of the case in the chamber. You expand the neck to keep the gasses blowing past the case.
You could in a pinch to prove the gas blow back theory, load a couple rounds this way. It’s not uncommon with cast or pistol loads to flair the neck to seat the bullet, then touch it with a crimping die to remove the flair or bell. You would just leave off the step of flattening out the bell. You artificially do what should be happening by itself.
searcher
Gold $$ Contributor
In almost 50 years of serious reloading - I've had that look on brass a number of times (easily more than 15 or 20) and all were related to either too light of a load or moisture in the powder. As another mentioned - that might seem suspect with the high velocity you are getting - but every barrel is different. You know it is hot when you start getting signs of pressure - and that is not one of them. One of my most accurate .223 loads for my bolt gun looks like that - and I know it is from too light of a load - but it is so crazy accurate, I have run it like that for over 4,000 rounds using that load.
so your saying to keep ramping up powder charge until i hit signs of pressure and hopefully this goes away! If it doesn’t, then look at other avenues. But as far as your concerned I should overly worry about it as long as I’ve checked the number of things off the list;
- light load
- head space
- neck tension
- work hardened brass
- annealing.
and if it still happens the just shoot it as it is and run with dirty brass. I mean if it’s not causing harm, and I’ve done everything I know of correctly I’m okay with it. I just want to make sure I’m not missing something and if I am to fix the issue.
I mean out of small chance this barrel is insanely fast and I am below pressure I’ll ramp it up. But 105’s at 3200-3250 sounds insane
Jager
Gold $$ Contributor
No. Don't do that.
Low pressure would be an obvious cause of your problem. But that would also be seen very clearly in your velocity. You mentioned in your first post you were getting 3150 fps. Low pressure is not your problem.
Low pressure is the problem, but not from the amount of the powder charge.
The output of the primer firing is moving the bullet out of the case mouth to soon. Low neck tension/bullet hold.
A long free bore/throat adds to the problem.
On firing, the bullet needs to be in contact with the rifling , while the full diameter bullet shank is still in contact with the case mouth. (Bullet jam)
The start pressure may be low because of the small rifle primer & tiny flash hole (if brass has it?) https://forum.accurateshooter.com/threads/flash-hole-size.3966076/#:~:text=The standard dimension for Lapua,0590″.
My best guess, from what i have seen online.
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I would try a little faster powder. Don't bother working up a load, just take a book medium load and fire a couple rounds and see if they come out sooty. Also could be a perfect storm of max and min dimensions, barrel, bullet, chamber, brass, all being off from normal at the 4th decimal place. All adding up to just enough clearance to cause the sooting. Sorry still on my 1st cup of coffee.
Frank
Frank
okie
Gold $$ Contributor
This weekend I was trying to get a load for my kid to shoot at 500 (throated for 140's--trying to make 107's shoot to reduce recoil) only had 1/4 of the neck gripping bullet. Barrel wouldnt shoot with a long jump. So I tried several powders... Fastest powder (varget) no soot. slowest powder (H4831sc) had lots of soot! -- best accuracy with fastest powder marc
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