Range Report New Sierra 155gr Palma

[Wild_Bill]

Hi all just tested the new 155gr Palma MAtchking from Sierra #2156 it is replacing the old one as the palma projectile but for now the old 155gr projectile will stay as a matchking. so they are longer than the old projectile by .055" and have .035" less baring surface base to ogive makin g them a lot higher in the BC department also they have a sharper ogive with the points closed up more to give them a BC almost identicle to the 175gr MatchKings. So My advice is anyone using a 155gr or 175gr projectile in your 308's try these they are amasing at 600 yards we got 1" elevation for 10 shots and around 4" wide at 1000 they are shooting around 3moa flatter that is over 30" the load we use is Lapua cases fed GM210Match Primers 46.2gr Varget for just over 3000fps in a 30" Lawton .307 Palma 12 or 13 twist barrel. We use M852 chambers and found running them .010" into the lands or .040" of the lands did not make any diference.

So the 308 now can out perform a 6mm dasher and almost the same as a 6mm dasher with 107gr MatchKings with the extra recoil though.

So any 308 SHooters make sure you try some i think you will not believe the performance you will get with just the projectile change.

 

[LoneWolfUSMC]

Re: New Sierra 155gr Palma

How do they compare to the 155 Scenars?

 

[kombayotch]

Re: New Sierra 155gr Palma

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LoneWolfUSMC</div><div class="ubbcode-body">How do they compare to the 155 Scenars? </div></div>

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Main=88364&Number=966431


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wild_Bill</div><div class="ubbcode-body">
So the 308 now can out perform a 6mm dasher and almost the same as a 6mm dasher with 107gr MatchKings with the extra recoil though.</div></div>

Drop is one thing, wind drift is another. People often compare the 155 Scenar in 308 Win. to a 260 Rem. because they get similar drops. However, if you run the ballistics, you get something like this:

Wind (mph) 10
1000 Yards
Cal. Bullet MV Velocity Energy Drop Wind
308 Win. 155 Scenar 2950 1364 640 -347.6 86.8
260 Rem. 139 Scenar 2750 1544 735 -344.0 65.4

Doesn't look like a 260 in the wind... even against a conservative 260 load.

How do they compare in terms of wind drift?

 

[kombayotch]

Re: New Sierra 155gr Palma

I'm not familiar with the Dasher... I think I've heard that its capable of over 3000 fps. with that bullet. But, here is what it looks like matching up the drops:

Wind (mph) 10
1000 Yards
Cal. Bullet MV Velocity Energy Drop Wind
6mm 107 SMK 2850 1450 499 -343.2 75.4

It still has the wind advantage. That new 155 Palma SMK is a great bullet though.

 

[Wild_Bill]

Re: New Sierra 155gr Palma

The Dasher is a BR case with the shoulder pushed forward .100 and the shoulder angle changed to 40 deg. the Dasher usualy uses 10% more powder for an extra 100fps at similar pressures some people realy push 6BR's to 2900 and 6 Dashers to 3000fps but 2850 and 2950fps resperctivly is a fairer and safer result.

The main thing is that with the new 155gr Sierra realy helps the 308 att he longer range with the aditional velocity that it can be pushed to with the 308 case. The 155gr projectile weight is realy a better weight to use than using the heavier ones as the case capacity can hinder the usefulness of the heavier projectiles.

As stated elswhere their are other 155gr VLD type projectiles and these can also be used i have found that the Sierra MatchKings are generaly easier to get to shoot in most rifles than other projectiles and i am glad that Sierra has finaly caught up to the pack and have realy come up with one of the ultimate projectiles for use in a 308 Win. with the wind drift i just placed into my program using .503 as the BC 200ft elevation 3 o clock wind 10MPH uses 7.3 True MOA drift and 27.5 MOA elevation and using the same temperature variables just changing the BC to .527 and Velocity to 2850 for a BR the results are 7.2 MOA and 29 MOA elevation so the 308 seems to have a slightly flatter trajectory but the 6mm BR has .1 moa less drift just over an inch but it would have to be confirmed with TRUE BC values Siera is generaly close so you could esentialy say that a 6mmBR with 107gr MatchKings is almost the same as a 308 loaded with the new 155gr MatchKings.

I have also noticed that in heavy fish tail winds heavier projectiles generaly seem to hold their trajectory and windage better than lighter projectiles i think that mass might come into the mix i can not give hard data on this but it seems to be repeatable on our range anyway.
Their is also a strange occourance on our range if we get frontal fishtails you are better with a projectile that uses more elevation but similar wind figures as the mounds are every 100 yards the frontal winds generate uplift and flat shooting cartridges get a lot of elevation due to thin the worst cartridges are 6.5-284's the 284 Win realy blows them out of the water due to using more elevation and similar windage using a 142gr MatchKing in the 6.5 and a 175gr matchKing in the 7mm.

Anyway hope you think like i do the new 155's are bringing the 308 into the 21st century.

 

[kombayotch]

Re: New Sierra 155gr Palma

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wild_Bill</div><div class="ubbcode-body">Anyway hope you think like i do the new 155's are bringing the 308 into the 21st century.</div></div>

That's a bit of a stretch...

The true BC of the new 155 is closer to 0.460 base on the testing I've done. That is what Bryan Litz was getting as well. There is also a bullet that Berger makes (155.5 Fullbore BT) that performs slightly better and was released before Sierra's.

If you also consider that 190 gr. bullets have a true BC of up to 0.570 and that you can drive them at up to 2800 fps. with the newer powders, I wouldn't say that the 2156's are leaps and bounds ahead of whats already out there.

I agree that its a great bullet, but lets not make it out to be something more than it is.

 

[Jedi]

Re: New Sierra 155gr Palma

About time Sierra finally joined the crowd, berger and lapua already high BC 155 bullets.

More of same

Now if one of the big bullet makers would say take a 210 JLK and fill with an alloy etc for a weight of 155

Then we would have something NEW