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155 Scenar .308 - what an I doing wrong?

thefitter

Sergeant
Full Member
Minuteman
May 10, 2010
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I had heard these were the sh*t. I can not get these to shoot at all. My groups are all over the place.

REM 700, 1/10, 20"

XBR powder
CCI BR2
FGMM Brass

I was doing pretty good with the SMK 155. Can't figure out why these suck in this rifle.

I've tried working a load and adjusting seating depth but nothing is working. What am I missing? Is there a trick to these long skinny bullets? Thanks
 
Re: 155 Scenar .308 - what an I doing wrong?

I've never used XBR powder, but, 155 grain scenars, with 46 grains of Varget behind them, will shoot 1/2" groups at 200 yards. The best I could get with the same load, with Sierra's was about 1".
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LongArm</div><div class="ubbcode-body">?? How fast do they have to go to be accurate? </div></div>

The 155 class likes to be driven upwards of 2950+ fps.

Chris
 
Re: 155 Scenar .308 - what an I doing wrong?

How many grains of Xbr are you using? ive never used the 155s and xbr with fed brass,ive used lapua and nosler.Very easy to get accuracy.you should be no more than 45.5 grains with fed brass.Also scenars shoot good at 2.80" or close to the lands,they dont seem to care ,in my experience.
 
Re: 155 Scenar .308 - what an I doing wrong?

IMR 8208 XBR.....I was in on the rush to buy that powder, no favorable results so far with the 6PPC or .308 that beat the N-series from Finland...............xray9
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Forwardeyes</div><div class="ubbcode-body">How many grains of Xbr are you using? ive never used the 155s and xbr with fed brass,ive used lapua and nosler.Very easy to get accuracy.you should be no more than 45.5 grains with fed brass.Also scenars shoot good at 2.80" or close to the lands,they dont seem to care ,in my experience. </div></div>

45.6 grains

That was the sweet spot for the 155 SMK. Yeserday I tried various loads and although all of them were crap this was still the least crappiest with the new scenars.

So today I tried 2000, 3000 and 4000 off the lands. They were all so bad that I just stopped.
 
Re: 155 Scenar .308 - what an I doing wrong?

They shoot solid 1 moa for 10 rounds in my 20.5" 308.

Just tried them in a new 26" 700 SPS Varmint a couple days ago, and was "rewarded" with 2 moa accuracy at 100. Need to do some tweaking on this one.

Both rifles are factory Rem 700 chambers/bbls. I was shooting both loaded to 2.80", and both are jumping about .250" to the lands.
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BigBore56</div><div class="ubbcode-body">I think your 1:10 barrel might like a heavier bullet. My 700 with 1:12 will shoot the 155 Scenar OK if I push them 2950 fps, which is easy with Varget (and my 26" tube). </div></div>

I would have thought that was it for it not that the 155 SMK did well.

It has to do with the shape of this bullet. I'm going to try and scoot it closer and try a hotter load.

The thing with this XBR is that I'm already at 60,000+ CUP

I could go faster with Varget at much less pressure.
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">You have pressure indications, how did you come to 60k, also FGMM brass sucks for reloading, get some Winchester or Lapua </div></div>

What What What!!!

laugh.gif


Not doubting you Tex but I have recently been the recipient of 600 1x Fired FC cases (GMM!) and I ain't tossin em!

I also bought my first three hundred 155 gr Scenars, so maybe I'll test them in some of my beautiful 1xF Hornady or Winchester cases.

I'm running the 155 SMK (2156) over 47.6 grains of Varget with no adverse pressure signs in two different rifles. Was thinking I'd start the Scenars at 46 and work up.

Still thinking that.
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">You have pressure indications, how did you come to 60k, also FGMM brass sucks for reloading, get some Winchester or Lapua </div></div>

This is what IMR has in their load data for a 155 SMK

155 GR. SIE HPBT IMR 8208 XBR .308"

45.3 2854 60,900 PSI

I'm at 45.6 with a scenar, data should be about the same right?
 
Re: 155 Scenar .308 - what an I doing wrong?

No, a Lawyer wrote that, if you are truely exceeding pressure you will flat primers, ejector swipes, hard bolt lifts after firing and so on, every chamber is different, find the start of pressure signs then back off your charge, I gaurantee those Scenars will fly if pushed hard. QQ FGMM brass is soft, thats there secret to out of the box accuracy, after two mild loads all my primer pockets were too loose to hold a primer in, Win brass lasts forever when loading 175/178 to 2625, and Lapua will go 6 or 7 reloads of hot 155s going 3050
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">No, a Lawyer wrote that, if you are truely exceeding pressure you will flat primers, ejector swipes, hard bolt lifts after firing and so on, every chamber is different, find the start of pressure signs then back off your charge, I gaurantee those Scenars will fly if pushed hard. QQ FGMM brass is soft, thats there secret to out of the box accuracy, after two mild loads all my primer pockets were too loose to hold a primer in, Win brass lasts forever when loading 175/178 to 2625, and Lapua will go 6 or 7 reloads of hot 155s going 3050 </div></div>



Are you saying that a 155 GR. SMK bullet loaded with 45.3 grains of IMR 8208 XBR will not give me 2854 fps at 60,900 psi?

What published load data can I believe then?
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: queequeg</div><div class="ubbcode-body">
Not doubting you Tex but I have recently been the recipient of 600 1x Fired FC cases (GMM!) and I ain't tossin em! </div></div>

Do what I do. Get the used FGGM 1X fired from your fave LEO sniper. Develop a load with A-Max rounds for hunting. Then leave the brass where it falls after shooting hog/deer/ceiling/whatever. Easy-peasy and you don't have to spend time looking for brass. You can spend more time killing shit.
 
Re: 155 Scenar .308 - what an I doing wrong?

With lapua brass jammed .3 in the lands I've ran up to 46 gr of xbr with the 155's @2975 out of my AE.Got a little pressure signs and back down to 45 gr @2905 or so.Shot .25 or less MOA @200 with 46 gr but @ 45 gr the group opened up to 1 MOA.XBR is very sensitive at that charge weight so you might try going up .3 and down .3 to see what happens.As cobra said find the max of your rifle,my most accurate loads have all shot at .5 gr or so over published max. If you start getting some stupid velocity or pressure signs back it down.
 
Re: 155 Scenar .308 - what an I doing wrong?

i'm pushing the 155 scenars in the 2850 range jumping almost .1. sofar with the first test its showing sum moa with all loads, and sub .5moa with 2 loads
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: seaaggie</div><div class="ubbcode-body">i'm pushing the 155 scenars in the 2850 range jumping almost .1. sofar with the first test its showing sum moa with all loads, and sub .5moa with 2 loads </div></div>

How far out have you test that load?
 
Re: 155 Scenar .308 - what an I doing wrong?

Get rid of the Federal brass and buy Lapua/Norma or Win brass.

Fireform them, or try load development on them on their second firing.

Not sure about the powder.

Dont jump these projectiles. Have them kiss the lands.
 
Re: 155 Scenar .308 - what an I doing wrong?

I have had success down near 43.6 gr Varget at magazine length with FC cases. Pretty slow laod, but shoots well at short ranges.

I have had much success at 47.8 gr Varget in Win cases (47.4-5 for Lapua cases) pushing 155 Scenars (and 155 SMK (2155)) to 2950 fps at 2.948 OAL. Since I have 29 reload cycles on this lot (100) of brass without loosing a neck or primer pocket, I can't be at seriously excessive pressures!
 
Re: 155 Scenar .308 - what an I doing wrong?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NTRP-CKA</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: queequeg</div><div class="ubbcode-body">
Not doubting you Tex but I have recently been the recipient of 600 1x Fired FC cases (GMM!) and I ain't tossin em! </div></div>

Do what I do. Get the used FGGM 1X fired from your fave LEO sniper. Develop a load with A-Max rounds for hunting. <span style="color: #000099">Then leave the brass where it falls after shooting hog/deer/ceiling/whatever</span>. Easy-peasy and you don't have to spend time looking for brass. You can spend more time killing shit. </div></div>

If I did what you do, I'd be far funnier, a better shot and apparently, something of a litter bug!

Still keeping the FC brass.
 
Re: 155 Scenar .308 - what an I doing wrong?

I'm almost done with load development using 8208 XBR and 155 grain Nosler J4s. I started out with an OCW test using new Winchester brass with 44.5 grains up to 46 grains in .3 grain increments.

My initial results mirrored most that I've read, with the low node at 44.8 and the high node at 45.5. The 46 grain loads gave me bad pressure signs (pierced primer, bad ejector swipe, flat BR2s). My CED M2 chrono sucks balls, so I got very few readings, but I got one reading of 2,789 with the 45.4 grain charge, and one reading of 2,793 with the 45.7 grain charge from a 20" gas gun. Further testing confirms that 45.5 grains is my high node, which is above book maximum. I'm seating at 2.278" to the ogive, which is 2.845" to the tip, and I'm at the point now where I'm going to run some seating depth tests when I get the chance.

FWIW, I also confirmed that new Winchester brass gives me wild results over once fired Winchester brass, so I'll never be using new brass again. Keep in mind that Winchester brass for 308 is roomier than Federal, so your charges may be a little less than mine. Start low and work up.