8mm Mauser Cartridge ignition delay time...

Dutchie

Dutchie

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I'm reloading some 8mm for my K98
150 Grain .323 Hornady SP
46.8 grains of BLC-2
Cases are trimmed to recommended length.
Federal Large rifle primers.

There is a noticable amount of air space in the cartrige after charging the case with powder.

When I test fired 20 the cartdriges yesterday, I noticed a few (like 3) of the rounds had a slight "delay" in ignition. It was only a fraction of a second, but enough for me to notice that something was funny.

The primers are new, the powder is dry....and the Mauser is exceptional!

Has anybody else come across this before using 8mm and BLC-2? Would it be the amount of airspace in the case causing this?
 
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I have no experience with your exact problem, but I doubt if airspace is much of a factor. However, ball powders are often paired with magnum primers for best ignition. Most reloading manuals recommend it. Try a magnum primer.
You are also using a very light bullet for the 8mm, one could speculate that a short bullet with light neck tension and low mass could contribute to inconsistent ignition. If you must stay with 150 gr, a Lee "factory crimp" may help a bit.
 
I bet it's due to a very long throat - the bullet has completely left the neck before it engages with the rifling, causing a momentary drop in pressure (the delay), followed by a sharp rise in pressure. Not a good situation.

Take an unprimed case and try seating that bullet just enough to be gripped and stay in place inside the neck, say 0.025" - then see if it will chamber. If it will, and the bullet is not seated further, then it would confirm my suspicions. In that case go with a longer (i.e. heavier 170, 180, 200, or 220 gr bullet) and seat it to within 0.050" of the rifling.
 
Hang fires are NOT good. Generally primer related in my experience. I'd try a magnum primer, and be certain that the primers are firmly seated in the bottom of the primer pocket. If not you can get the symptoms that you describe.
 
The COL for this particular cartridge using the 150 grain SP is 2.975, and it's crimped on the cannalure.

The primers are seated to the bottom on the case.

The maximun COL for this particular rifle so that the bulllet is sitting on the lands is 3.075, there by leaving a jump of approx .100 which in my experience is not that bad. not by any means perfect, but I'm crimping on the cannalure which leaves you no other choice.

What was a standard bullet weight for the wartime K98? I'm starting to think my bullets are to light?
 
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They are not too light but you would do well to use a heavier bullet to seat further out I believe the WWII load was 195-198 gr. seated out to 3.169"..... in any case just try a magnum primer with BLC-2.

You can also skip the crimping and seat it the 150's out farther as suggested.

Ive never crimped a bullet in an 8x57 case....no need....I shoot 175's and seat as long as the magazine allows me which still does not get me that close to the lands....

This is also in a K-98 .
 
Wow, even with 175's, you can't touch the rifling? I am able to touch the rifling at 3.075 Overall length with 150's.

Your comencment of rifling must be either be eroded to the point to smoothness, or manufactured that way, so the bullet does not contact until the projectile is well on it's way.

What make is your K98? I'm going to check my other K98 and see what the rifling starts.
 
I had the exact same problem with a 8x57, using that powder and an even lighter bullet. Did it for every one of the 20 rounds.

Two solutions:

use a magnum primer.

If you use a sizer with a neck button, remove the button, or resize the cases withthe decapper rod removed.

You can use both fixes. Should solve the problem.
 
Dutchie, your mauser must be a late model with a shorter throat. Many of the earlier rifles had longer throats to accommodate the longer bullets. I have two 98s with the same date and manufacturer that have different throat depths. They were both originally built in 1937 but one was re barreled at some point. All numbers match but the finish texture and blue are not consistent. The re barreled throat is much shorter.

In my experience, even though the books recommend loads for BLC-2 with lighter bullets, it is a far better propellant for heavier bullets and really likes to be in a situation where it's almost filling the case to the base of the bullet. That's another reason why ball powders seem to work better with magnum primers.

I've never even though about Andy's theory before. I guess it's relevant in that the powder would need the increase in pressure to burn efficiently enough for full ignition but I don't think that I personally would be able to notice the difference, time wise. Interesting concept and potentially a very definite accuracy deterrent. Hmmmmmm. That opens up a can of worms.
 
I would definitely try magnum primers first. I have had the same problems in using a ball powder (H110) in a .44 mag revolver when I used standard primers. In fact in the winter @ -40C they wouldn't even ignite the powder. I ended up with a bullet stuck halfway down the bore! Fun!!! Switched to magnum primers with the same load and no more problems. I'm betting magnum primers will solve your hang-fires! Good luck!
 
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