338 Lapua Sanity Check

[kidkl]

Hello all,

I am looking for some sanity checking on my 338LM loads for my trg42. I am using a 250 grain Scenar and either VV N560 and H4831sc, Lapua brass and GM215M primers.

For the H4831SC starting load is 82 grains working up to around 90 (trying to get around 2950-3000fps if possible). The starting load should be around 2700fps and working up to around 2950-3000fps at 90 grains.

For VV N560 starting load is 82 grains also working up to 90 with about the same fps as above. I have searched through the "Loads for .338LM- .50 Cal" and seen that a few other people are running loads within this area. I also found the following posting from Zak Smith on another board:

Lapua 250gr Scenar:
- H4831SC: start at 88gr, my load is 90.5gr
- Retumbo: start at 92gr, my load is 96.0gr
- RL25: start at 92.0gr, my load is 94.0gr
- N170: start at 95.0gr, my load is 98.0gr
- N560: start at 86gr, my load is 89.0gr
- H1000: start at 92.0gr, my load is 94.0gr -- We got poor results with H1000 at 1000 yards in both the TRG-42 and my AI.

Which all seem to indicate that I should be fine. However in doing some triple checking I came across: http://www.lapua.com/fileadmin/user_upload/Relodata/Rifle/.338LapuaMagnum.jpg saying that max load for a 250grain scenar with N560 is 82.2 Grains. My sierra reloading book for a 250grain SMK says that 82.1 grains is the *STARTING* load. I know that there is a difference between different bullets and how much powder to use but it should not be *that* different.

The other thing I don't get is that in the above Lapua table, the max load for the 300gr scenar using N560 is 82.3 grains... So the max load using N560 for a heavier bullet is .1 grain more than the max load for a 250grain bullet? That doesn't make sense to me.. are VV/Lapua's numbers wrong? As it seems to me anyone running anything above 86 grains of N560 with a 250gr Scenar would be dangerously hot end of things according to VV/Lapua. Should I look at pulling down my loads with the VV N560 and reducing them?

Thanks,
Kris

 

[Mag 300]

Re: 338 Lapua Sanity Check

take a look abouve at the reloading depot thhings like this are there for you .
Hope it helps
Bill
.338LM TRG42

NOTE: Using a CHRONY and have doubts about the accuracy of it. Also note temp readings.



Hunting Load: TEMP 50F
.338LM SAKO TRG Date: 10-26-08
Bullet-225gr Nosler Accubond
Powder-88gr H4831SC
Primer-F215M
Brass-Hornady
OAL- 3.625/3.910
FPS:2835 AVG
(Just put this load together and used the same dope as my Target Load. Real close to being the same. (within 1.5", tested on 30mph windy day)
(Will test more for accuracy, but looks to be VERY ACCURATE to 500yrds at least)


Target Load: TEMP 90F
.338LM SAKO TRG Date: 6-10-08
Bullet-250gr Sierra Matchking
Powder-88gr H4831SC
Primer-F215M
Brass-Lapua
OAL- 3.695/3.930
FPS:2939 AVG
(Sub .75 groups to 750

 

[kidkl]

Re: 338 Lapua Sanity Check

Bill,

Thanks for your response, I did check the reloading depot and mentioned it in my above post:
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kidkl</div><div class="ubbcode-body">
I have searched through the "Loads for .338LM- .50 Cal" and seen that a few other people are running loads within this area.
</div></div>
My questions and concerns are mostly around the VVN560 as the VV reloading data doesn't seem to match up (I put my h4831sc loads up as well just for another set of eyes). I did do some more searching, thanks to your post, and came across: http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1126169#Post1126169 but I am still wondering about the VV reloading data.

 

[Mag 300]

Re: 338 Lapua Sanity Check

Kidkl

I apologize in that you had this in your post , wasn't trying to jerk you around or waste your time.
Glad that found something you could use.
I myself have no experiance with VV powders
Bill

 

[hexades1]

Re: 338 Lapua Sanity Check

I have been using 88,0 grein N560 behind a 250 Scenar for many years with no problems.

Lapua tells what their pressure barrel tells them. When they change the test barrell the max load will be different.

You are on your own but 88,0 grains in MY rifle is not too much. It is tight necked and match chamber so a factory chambered TRG-42 should have no worries with this load of N560.

 

[ChrisGarrett]

Re: 338 Lapua Sanity Check

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TA</div><div class="ubbcode-body">I have been using 88,0 grein N560 behind a 250 Scenar for many years with no problems.

Lapua tells what their pressure barrel tells them. When they change the test barrell the max load will be different.

You are on your own but 88,0 grains in MY rifle is not too much. It is tight necked and match chamber so a factory chambered TRG-42 should have no worries with this load of N560. </div></div>

I see where the OP is confused with the SCENAR 250 and N-560, as my 2006 VV pamphlet has 74.5-82.2grs, but the 250 LockBase is 78-85.9grs. In addition, Sierra V has the 250 MK/GK and N-560 at 82.1-90.0grs. Sierra is notoriously conservative, too, so go figure?

Now, like you said above, different barrels, different bullets, different firearms, etc., but this being said, it seems that VV is a little soft on this specific listing, in light of personal experiences here.

As always, start low and if you're nervous, use the lowest low and work up in 2gr increments for this cartridge.

Chris

 

[kidkl]

Re: 338 Lapua Sanity Check

I did some more searching around and found some old digital copies from 2002 and 2004 of the lapua/VV reloading manual. The max charge for N560 in 2002 was 85.0Gr (the reported speed also matches what the Sierra reloading manual for that charge weight), in 2004 was changed down to 83.3Gr and in 2006 was changed again to the current 82.2Gr.

Chris is also right where I was confused by 2 things in the VV reloading data, the lock base which given the weight and BC should have a pretty darn close construction to the Scenar was ~4Gr higher for max load. But what really got me was the fact the max load for the 300gr Scenar was higher than the max load for the 250gr.

I can understand the VV numbers being lower than the Sierra data assuming that for the same weight the Scenar is longer and has more bearing surface (I don't personally know as I don't have any 250gr MK's to compare too). However, I was not expecting to see an 8Gr difference or the starting Sierra load to be just under the max load from VV.

I will take Chris's advice and load a few in the lower VV charge weights and work my way up to the "higher" ones being reported here and we will see where things end up. I will be sure to post my results once I am finally able to get out and shoot.

Kris

 

[hexades1]

Re: 338 Lapua Sanity Check

Sierra jackets are softer Ms95 (95% copper, rest zinc). Lapua has harder (not necessarily better) jakces of Ms90 (90% copper, 10% zinc). The engaving of the rifling to the bullet is harder on the Lapua bullet than on the softer Sierra jacket.

Lapua pressure barrels are usually tight with minimum chambers. Factory rifles like TRG-42 are usually much bigger even though still within spec. They have to play on the safe side.

 

[cali_tz]

Re: 338 Lapua Sanity Check

This was helpful for me. Using the latest VV560 loading data (Rem 700 Police Special, 215M Fed, Hornady case, 250scenar), I found at the range that my measured fps for the min/max loads were 200fps lower than what the VV reloading guide specified. That's alot isn't it, so much so I suspected the chron was malfunctioning? It was so off, I went back to shooting factory 308GM ammo and it was spot on velocity wise, so figured the chron was ok. Temp was 65 deg F.

If I recall correctly my VV reloading guide (just a month old) says that they used a 26" barrel .. same as the Rem 700. I am really curious as to what is going on.

ALl this being said, my 82.0 gr loads were very accurate in the 100 yd check of my scope setup. I have never been able to shoot groups that tight with the Rem 700 Win 308.

<span style="font-style: italic">edit: actually the VV guide says that 250 Scenar should yield 2841fps at 82.2 grains of N560. But that is with a 27.5 inch barrel (1 in 10 twist). My Rem 700 is spec'd at 26", but would that explain my results for 82.2 grains which was 2604 fps, over 200fps lower barrel velocity? If not, what else could explain this large discrepancy in speed? If I went up over 82.2 to an N560 load that would hit 2800fps, would there be over-pressure risks?</span>