Lapua Large rifle primer brass vs. Palma small rifle primer test

[watercam]

Finally had what I needed to test one type of .308 Lapua brass against the other. Used BR4s in the Palma brass with 46.5 gr. of Varget vs. Tula Large Rifle primer and the same powder charge. 155.5 gr. Fullbores were the projectile through a Bartlein 32" barrel, Barnard action benched. End result at 300 yards? Not too different. The velocity of the BR4s was 2950 fps (42 degrees F. - usually cranks 2990 in 75+ temps) and vertical dispersion of .3moa. The Tula load clocked 2975 fps and same vertical but .4moa higher over all on the target.
FWIW - which, apparently, is not much!

 

[22BRGUY]

Not familiar with that load but was wondering if you consider it a "top end" load or rather a milder load in your rifle. My thought is that the Palma stuff may show it's advantage (if any) on top end loads with higher pressures. Thanks for great test info though..very interesting.

 

[watercam]

In my rifle 47 gr. w/ small rifle primers definitely shows pressure signs on days above 75 deg.. I know Varget is supposed to be temp. insensitive but when it heats up I know it! Lapua brass, Berger Fullbores, BR4 primers. When I was using Fed. 205Ms the end result was the same.

 

[mysticplayer]

Very interesting test.

would you consider repeating the test but running a lower charge in the LR brass until the impact was the same? Maybe 1/2 gr less?

Love to see what velocity you get.

What struck me was the much higher impact of the LR vs the SR load with such a small velocity difference.

You have seen pressure signs with the SR primer in hot weather. Have you had a chance to see if the same result is present with the LR brass?

Thanks

Jerry

 

[Shynloco]

watercam,
I appreciate the post, but am not surprised the results you found. I'd be curious to see the numbers at say 600 yds - 1K as well as the accuracy differences using the two different primers. And to be fair, based on what I've learned on my own using a .308, I'd be inclined to use 175 gr SMK's due to the distance which I believe produce better accuracy at 600 - 1K. That's based upon shooting results of some of the guys who shoot the longer distances. And no I don't shoot either of those distances, but am just plainly curious as the results based upon an anticipated difference based solely on the belief that longer distances create a greater variation in fps and tend to give a truer picture of which primer produce the better accuracy. Thx.

Alex

 

[watercam]

Jerry and Alex:
It is not that I would object to testing Remington primers as I have heard some good things about them. At this point in the component crisis I happened to have a source for the Tula primers (which have the lowest flash of any large rifle primers according to German Salazar's tests of a couple years ago) and I happened upon some large rifle Lapua brass from the good old days when they were (are) extremely concentric in wall thickness and weight.
I, too, was struck by the point of impact change as that kind of elevation shift would need more than 100 fps difference at 300 yards. I am shooting a Long Range Palma Regional in a couple of weeks and will need to shoot both brass types during that week. Should be interesting when changing over! The ambiant temps at the match in Sacramento will be higher than I have here in Oregon right now, will let you know.
In reference to the Fullbore/155.5 gr. bullets, I have tried the 185 Juggernauts as well and they shoot very well in this rifle. For what ever reason my scores went down with them and I suspect the extra recoil is, for me, the culprit. Am committing to the 155s for the time being. Will post match results when I have them.
Mike

 

[Rtheurer]

Mike
I did the same test last spring. My normal Palma load is 46.5gr of Varget with Lapua LR brass and a CCIBR2
I tested with the exact same components and powder. Found that I had to increase my SR Brass a 1/2 Grain of powder to get the same Velocity and pressure. This could very well be to the my certain Lot of Tula SRM primers used in the SmallPrimer brass however. ES and SD where ever so slightly smaller on that day and the next outing after raising the charge up 1/2grain. Using the flame thrower Remington primers it may be the other way around...

Took the SmallPrimer Brass to Spirit of America Match last fall to get one firing on them prior to this summers shooting tour all over the USA and Canada. Every thing seemed just fine. Some of the guys onthe team are saying they are getting 15 plus firings on there SP brass. I have been getting about 8 before I retire the Large Primer since we run them pretty hot to get the 155's to 3000 fps ish.
Looks like your getting about the same results as I did. I could tell no diffrence on the target at 1000 yards however.
Russ T

 

[Scott Harris]

Recently tested large primer lapua vs small primer lapua at the berger nationals: used 1/2 and 1/2 at the match...not at the same time of course. I found no difference in accuracy, but did have to load .5 grain less powder in the large primer brass to achieve the same velocity as the small primer brass. The small primer pockets do last a lot longer than the large primer pockets. Also, I don't use small primer brass when the temps get below 40....just to be safe.

 

[Rtheurer]

What Primers did you use? I find it funny that you are seeing the same thing as I found with the powder charges.

RussT

 

[Quickoz]

Does anyone use CCI450s with there SR brass? Down here in Australia, nearly anyone who uses SR Lapua brass runs the 450 primer. Has no issues in all temp ranges with Varget. A few also run the Palma brass with 243AI, 260AI, etc.

 

[watercam]

My only reason for the test is to make sure I have a way to shoot when components are scarce. Small rifle primers (for me at least) have been harder to come by than large rifle. I will continue to shoot the Lapua Palma brass as long as I can feed the primer pockets! Thanks for the information on others testing. Can't have too many results!
Mike

 

[918v]

I believe Lapua SR brass has .5grs more water capacity, hence the POI shift. You should rework the load.

 

[watercam]

That would explain the weight difference. The large rifle brass average 4 grains heavier (Lord knows the neck walls were thicker). In any event I loaded some with .3 grains less powder and will see how they work at 1000 yds. during practice.

 

[Scott Harris]

I believe Lapua SR brass has .5grs more water capacity, hence the POI shift. You should rework the load.

I measured the H20 capacity of both cases and they were identical: 56.14 gr as measured by a GD503. There is a difference in the weight of the brass, but the volume is identical. I "believe" the charge difference can be accounted for by the extra energy imparted by the large primers.

 

[Rtheurer]

Same result with mine. Internal Capcity is the same on my brass weighed on a Lab Scale. D.I Timberline 203.

 

[rminut]

That would explain the weight difference. The large rifle brass average 4 grains heavier (Lord knows the neck walls were thicker). In any event I loaded some with .3 grains less powder and will see how they work at 1000 yds. during practice.

I believe you are correct in saying the wall thickness is different. I've always used a .335 bushing with LR Lapua and the same bushing used with SR Lapua let the bullet move with light pressure. I had to scrounge a .334 bushing.

 

[918v]

http://forum.accurateshooter.com/index.php?topic=3789613.0

Scroll down to Steve Blair's post.

Now I don't have any to test, but I do have the LR brass and Winchester and can interpret other people's findings, like German Salazar's. Palma brass seems to have more capacity.

 

[mysticplayer]

I believe Lapua SR brass has .5grs more water capacity, hence the POI shift. You should rework the load.

I measured the H20 capacity of both cases and they were identical: 56.14 gr as measured by a GD503. There is a difference in the weight of the brass, but the volume is identical. I "believe" the charge difference can be accounted for by the extra energy imparted by the large primers.

With the combo I use in my FTR, my powder charge is very compressed and with component shortage, ran out of my fave primer.

So I started to play with other brands and type. What I found was the energy of the primer had a direct influence to the end performance of the load. If the powder charge was the same, hotter primers leads to higher speeds AND pressures.

Just like adding more powder.

Now, I can play with my powder charge by going to various primers to obtain ideal ignition vs load density.

That compressed load is not bad now by going from standard LR primers to magnum. Charges were reduced but speed and accuracy remained the same.

Primers matter and now become part of my tuning regiment.

Jerry

 

[antitactical]

I've gotten better results with the 450s vs br4s in my 308. 46.5grs of varget and a 155 vld hunting bullet. I got a slightly better accuracy with the small primer brass vs large. Like everything, its all in what your gun likes.

 

[Laurie]

http://forum.accurateshooter.com/index.php?topic=3789613.0

Scroll down to Steve Blair's post.

Now I don't have any to test, but I do have the LR brass and Winchester and can interpret other people's findings, like German Salazar's. Palma brass seems to have more capacity.

No more than the usual variances between production lots so far as I've seen. I have both types covering three or four production lots and they have near identical neck thickness, weights, and fireformed case water capacity. Any overall weight difference from LRP brass is such that it appears to come solely from having a smaller primer pocket, therefore a bit less metal removed from the case-head section.

Over the years, I've seen many variances in Lapua brass between lots with several grains between them in weight and up to one and a half thou' average neck thickness differences between lots. I'm pretty sure the two current types are made together as part of a run with a part of the output diverted when it reaches the primer pocket and flash-hole creation operations rejoining the others subsequently for finishing and packaging.

Having obtained very early production examples of Lapua's .260 Rem and 6.5X47L immediately after they were introduced, I found their consistency to be superb, even better than the Lapua norm. I had hoped that the Palma 308 was going to be made on all new forming dies and would be in the same league, but unfortunately it's not quite as good, and as I said was found to be identical with standard Lapua LRP brass that had left the factory in the same shipment.