Home Forums Reloading Big Game Rifles Results: Approaching Manual Max. Load Data

Results: Approaching Manual Max. Load Data

I�ve been reloading some 165gr Partitions over Vihtavuori N160 powder in my Remington 700 30-06. Book max. load for a 167gr Lapua Scenar bullet using this powder is 63.7grains for 2901fps from a 24" barrel. There is no data listed for the Partition bullet.

I worked up a load using my own pressure signs of sticky extraction, heavy bolt handle lift, flattened primers and primer pocket looseness. I got to 63grains before stopping without seeing any of the above signs. I thought I had my load settled.

Saturday I returned to the range with some more reloads to run over my friend�s chronograph (Pact 1XP). I was quite surprised to see an average of 2970fps with low SD. The barrel on my rifle is standard factory 22�. Temperatures on both days were in the range of 17c to 21c (about 62f to 70f).

I�m a little worried that the velocity figures are telling me I�m probably running pressure too high. Would this a good conclusion? Or is 2970fps quite possible?

Thanks for any observations / comments.

- stu

You might be running on the hot side for normal 30-06 pressure standards.

Nosler #4 shows a max of 58 grains giving 2767 fps from a 24" Lilja barrel. Lyman #48 shows a max of 61 grains under 165 Ballistic Tips giving 2895 fps and the same charge under a 168 grain Sierra HPBT giving 2891 fps, both from a 24" test barrel.

I just set up a linear regression through the combined Nosler and Lyman data to check the general trend of charge weight vs. velocity. The best-fit line and actual data points fit together quite nicely. For a 63 grain charge, two grains above the Lyman max, the linear model predicts a velocity of ~3002 fps from a 24" barrel. Your load showing 2970 fps from the 22" barrel seems consistent with this prediction.

I just did a second linear regression through the charge weight vs. pressure points listed in the Lyman data. IF you believe the linear model holds water, it predicts about 63,600 psi for your 63 grain charge. This figure is at the upper end of what Lyman reports as max pressure in a variety of loads for several diferent 300 magnums. The model also predicts that about 61.8 grains would get you closer to the 60,000 psi SAAMI max for the 30-06. It would be interesting to see if the 61.8 grain charge shows right at 2900 fps from your rifle.

Whatever you do, do NOT take this post as gospel. I'm not a professional ballistician and I'm not representing myself as one. All I've done here is a little computational exercise with some published data.

If you do run further chronograph tests, particularly with 61.8 grains, please report your findings on this thread.

mathman

In my experience, primers start to flatten well before any of the other indicators you mentioned. If you are not seeing flattened primers, you probably have a "fast" barrel. Nonetheless, it would be interested to try the 61.8 grain load as suggested by mathman and run it over the chronograph.

What primers are you using?

StuC,

I was at the range today with my .280. Trying some N-160 in it for the first time in quite a while. I looked back at some of my old data, and if I didn't make a clerical error I had previously loaded 154 Hornady's over 58grs of N-160 for right at 3000fps, and no pressure signs. Today I had 59grs of N-160 with 140 Accubonds and 139 Hornady IB's. A shiny spot on the case head and noticable recoil so I broke out the chrony. 3200fps! Smokin'! Don't know if the temp had anything to do with it as its in the 90s here today. But that needs to back up at least 2 grains in my gun. And you're over max grainage for R-22 which is slower than N-160. Id be careful...thats right on the edge, and smokin' fast for an '06 22"bbl with 165s. Interestingly enough, I didn't have excessively flat primers or cratered primers. But that shiny spot was clear as day! And the chrony don't lie.

And I don't know where you got that load data, but Nosler #5 says 30-06 N-160 max load for 165s is 58grs!

IIRC his data is the listed max in the Vihta manual with a 167 Scenar.

Vihtavuori data seems on the whole to be all over the map, and tends to be quite conservative.

Yes, it's possible.VihtVouri data for the 30.06 is CIP 405MPa,(58,725psi).While CIP is a bit looser than SAAMI,it's still less than SAAMI 60,000psi.With my factory M-700 30.06 ,with N560, they list 2672 for 185 Scenar,I get 2740 at 1/2 grain less with 180 SST.That's with much less primer flattening than factory loads.

Hi fellas,

I have had similar experiences with VV, with the target velocity being achieved well before book value. However, I should add that I have become a total convert to the virtues of this particular Finnish company. I use N160 to great effect in my 6.5x55, whilst N550 is the primary fodder for my '06; a 56gr dose of the latter pushing a 165gr Interbond at a mean of 2912 fps. Generally, case life is superb, only warranting a trim every 4-5 reloadings, whilst accuracy remains sublime in both chamberings.

Mathman, thanks for the regression modelling reminder - I haven't touched those in a long while! However, your point is clearly illustrated. In fact, the original context of pressure "tell tales" means very little, if significant departure from authoritative velocity data is apparent. Whilst flattening of primer radii, case flow (determined by increased neck OD in loaded state) and primer pocket interference are entirely valid signatures of material stress, they remain "rude" at best. Hence, 280 has hit the nail on the head and I quote, "the chrony doesn't lie". Here endeth the lesson...

A little safety margin is no bad thing and believe me, I have not yet seen the animal capable of discriminating between my 160gr 6.5mm and its faster and flatter 165gr .308 sibling, if both are administered properly.

Regards,

Jacobite

I went and checked the VV load data book. Seems you are in fact correct...for some reason, the Scenar's max load is some 4-5 grains higher than other similarly weighted bullets. I don't shoot Scenars...I have seen them I think...arent they long bullets, with a short bearing surface? long boat-tail and long from the point to the ogive? Maybe the short bearing surface is the reason...if it in fact has a shorter bearing surface.

Some great information and comments by all.

My only published data for this powder comes from the Reloading Guide published on www.vihtavuori.fi
I had downloaded the guide last year and was basing my max load on that (63.7gr for the Lapua Scenar 167gr bullet). Well, after reading some of the replies here I went back to the website. A new 2006 Guide is available, and it�s listing the N160 max load with that bullet as 61.7gr � a drop of 2 grains! (Interestingly, it�s also very close to the regression figure mathman came up with. I�ll need to study this a little more now).
I don�t have access to Nosler or Lyman manuals, though I may just need to find one cause I�m not so confident with the VV published data anymore.

It might be a while until I get the chronograph set-up again, but I�ll be dropping the charge weight back a couple of grains and see if the velocity sits around the 2900fps mark.

mudhen � primers were Fed 210.

280Rem � I shoot those Scenar bullets in a 308. They do have a slightly shorter bearing surface, but I think VV just messed up the data and have now revised it.

This rifle is going with me to Namibia in three weeks to shoot a couple of Springbok and Gemsbok. I�ll be spending some more time at the range before I leave.

Thanks again.

- stu

Stu,

Sounds like a plan to me. It's interesting that the recipes vary between each set of published data, as my N160 load for the 6.5x55 disappeared in the 2004 edition. However, Norma still uses an approximate version for its Oryx load. No doubt the consequence of a litigious Society - discuss.

It's interesting that you are off to Namibia for plains game and I wish you every success and a safe return. Naturally, a field report c/w pictures is the least we can expect <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />. In fact, I also have a trip booked this year for my 40th, although not as temperate! In October, it's off to Estonia for elk, boar and red, with both the '06 and 6.5 in tow. I have even dusted off my old Dad for the occasion, along with his Marlin 95 in .45-70, so in every respect, this should be a "classic" event.

Have fun and take care,

Jacobite

Jacobite,
I�ll be sure to post pictures and a report when I get back. I haven�t done any Eastern European hunting yet. Hunting somewhere in the Carpathians for stag is high on my want to do list. Estonia sounds like it should be fun for you and your Dad.

- stu