Palma brass firing delay?

[ColWhitecakes]

Is it just me, or has anyone else experienced, or suspect that, they have an ever-so-slight delay in ignition with Lapua palm brass? With the shortages of components, I, like many others I've come across, have had to make load changes as of late. So, I got my hands on some small rifle primer Lapua, which I really didn't think would be a bad thing. However, i could swear that there is a split moment between firing pin drop and recoil. Its like I can hear the striker click before it fires. In any case, I've never noticed the sound before, and I just didn't quite have enough time, or much in the way of spare bullets, to work up a load like I would have like to before todays match. My current load consist of 40.7grs ARcomp, 178gr AMAX, and a Tula sr primer. Oh, and I did have to slightly ream out the flash hole with my Lyman flash hole deburrer/uniformer. Was that a big no no? I don't know if I can find any, but I'm thinking maybe I need to try a sr magnum perhaps?

 

[LHSmith]

Possibilities: 1/ primer tool is not fully seating primers. Hand primer cams will wear if not lubed regularly.
2/ your primer is slightly larger than your primer pocket...not allowing it to fully seat 3/ the primer does not bottom in the pocket due to a small radius of brass at the bottom of the pocket......run the proper primer pocket uniformer in and see if it removes any brass 4/ strip the bolt and inspect for debris

 

[Eddie Harren]

Not uncommon in cold temps.

 

[NateG]

Yup. The three main causes are improperly seated primers (as LHSmith described), insufficient firing pin impact (weak spring, crud in the bolt slowing it down, or insufficient protrusion), and cold temperatures.

I've got a gun that really likes a load with the small rifle primers, but when it gets cold, problems sometimes pop up. Then again, there have been days where it's been extremely cold, and it worked great. But, like NASA's o-rings, the problems seem to be much, much more common when the temperatures drop enough.

That probably means that either my primer seating and/or firing pin impact is marginal, and the cold temps are enough to cause occasional problems. (perhaps 1 or 2 of 100--but that's too much chance of dropped points)

A few local guys swear by them, though, never having a single misfire or hangfire, even in the winter. Perhaps their firing pins impart a bit more force than mine does.

 

[Travelor]

When Remington came out with their BR basic brass a number of years ago I got some thinking the small primer would increase the accuracy of a problem child rifle I was fighting at the time. I experienced hang fires to the point the delay was like shooting a flintlock muzzle loading rifle. I tried everything in my bag of tricks, including SR mag primers and different brand primers to no avail.

I finally gave up as it appeared the small primers were just not capable of proper ignition on a large rifle case. I went back to large rifle primed cases and the hang fires went away.

I know this does not help, but it is just my experience.

 

[ColWhitecakes]

Great replies! I will look into all of those possibilities. Wonder if a ball powder like 2000 MR will ignite better than the sticks of ARcomp? I'm questioning myself on it now, but i believe i did uniform the pockets and the primers seem to botttom out. The are seated well eithin the cup. Are the Russian primers particularly hard by any chance?
The temps i shot in started from 27 in the morning to about 55 by the time i got to 600yrds. Same preceived results all day.
I'lll see what i can figure out and update at some point.

 

[NateG]

Are the Russian primers particularly hard by any chance?

Oh, that's the other thing I left off... some primers are harder than others. And, yes, the Russian primers tend to be pretty hard. (but Wolf/Tula SR--non 223, non magnum--are pretty soft)

So, improperly seated Russian primers with a light firing pin and a standard-to-light spring on a cold day is most likely to have problems.

 

[Laurie]

+ 1 on the temperature issue. The small primer is marginally effective for 40gn and up charge weights and is heavily affected by temperature and how easily the powder ignites.

I'd strongly suggest a magnum primer rather than standard for the same reasons.

Ball powders are generally harder to ignite than stick types - traditionally at any rate, but there have been so many advances in powder technology in recenty years that a lot of the old 'rules' either no longer apply, or at any rate matter less. So, you want to steer clear of Palma brass + standard SR primer + low temperatures + ball powders.

Using a standard flash-hole reamer and/or decapping pin is not recommended for Lapua 308 Palma brass, likewise 6mm BR, 220 Russian / PPC, and 6.5X47mm Lapua. These four cases are unique in emplying a small diameter flash-hole alongside the small primer - 1.5mm (0.059") diameter compared to 2.0mm (0.080") for everything else irrespective of primer size. So, you need a small flash-hole reamer from Sinclair or K&M. You also need a smaller dia. decapping pin for Palma brass otherwise you risk suffering one of the following ailments: broken pin / stuck pin / hole crudely reamed out by oversize pin. (The standard pin's nominal dia. is 0.0625".) My own experience of the Palma case FWIW is don't bother with any reaming - they're very consistent out of the box. I've run two or three hundred over a Sinclair small flash-hole reamer and couldn't see any difference at all. If you want to debur the inisde end of the hole too, I think that K&M is the only company that produces a combo tool for this size flash-hole (its PPC flash-hole debur / reamer), but while some people reckon that Lapua's drilled holes have the occasional example with burrs, I've never found this an issue in any of the company's cases I've used and that runs to a few thousand examples over the years in five different cartridge designs. Likewise I had a single box of Lapua .223 Rem Match cases in an older (gold cardboard box) lot that had 3 cases ex 100 with smaller diameter flash-holes than the rest, otherwise they really have been consistent across the board.

If you've reamed the holes out with a 0.080" tool, you should have improved ignition in cold conditions, but reduced / removed a lot of the benefits of the small flash-hole case which was produced to reduce MV extreme spreads and SD values for long-range shooting. If you've worked a hot load up in small-hole conditions and then reamed the flash-holes you should reduce charges by around 0.5gn as the size of the flash-hole has a noticeable effect on MVs and pressures, the Palma brass usually needing charges increased by around the half-grain mark to attain the same MVs as provided in standard large primer Lapua brass.

All the other points people have made about checking out primer seating depths etc are well worth looking at too.

 

[KevinThomas]

I saw this one and would have been happy to add to it, but Laurie has already managed to cover everything that I may have needed to say!

+1, and I'll let it go at that.

 

[ColWhitecakes]

Thanks again, all! I'm looking forward to seeing what I can come up with on it.

 

[1shot]

Just got a text from my shooting partner out in chilly Colarado. He was doing some testing with 47.5 gr. of BL-C2 in Lapua Palma cases using CCI 450 primers. No reported ignition problems of any kind were experienced.
I hope this helps,
Lloyd

 

[Darrel Martin]

I experienced hang fires with wc846, which is a military pull down ball powder, in Palma brass with Fed 205m primers. Switched to Rem 7 1/2 primers and issue resolved.