.308 Heavy Bullet Loads

[GermanS1]

My usual Palma load is a 190 Sierra (moly) with 42.5 gr. IMR 4064 (2640 fps) or a Berger 175 with H4895.

For the coming season (Nov. - Apr.) I'm thinking of using the Berger 190 VLD and N550 or H4350. My chambers have a slightly long throat (0.114" freebore) and either 190 will keep the shank at the base of the case neck.

I'd like to hear from anyone who has worked with the 190's with either N550 of H4350. I have plenty of light brass, WCC 58 and WCC 60, I can get 49.5 gr. of N550 to the base of the neck and about the same of H4350. I'm not suggesting those figures as loads, of course, just indicating case capacity.

I see that the VihtaVouri book shows 47.2 gr. N550 as a max load with the Sierra 190 and the moly 185 Scenar. No data with the Berger VLD, but that is a decent guide.

Any thoughts?

 

[JohnWayne]

German, I shoot a 30 inche 11 twist bartlein that has a throat about like yours. It loves 190 sierras and N550. I am having great luck right at 45 gr. and 2800 fps. In the lapua brass I have I can get 55.2 gr. of N550 in the case, but thats with a drop tube. I'm not sure how you're filling them. I have gone as high as 47 gr. but much above 45.8 I got vertical stringing.

 

[GermanS1]

All I'm doing for now is pouring it in from the pan with a little funnel and eyeballing it to the base of the neck or a little below. Looks like I have plenty of capcity with my brass. Lapua brass is quite a bit thicker, so I'm encouraged by the fact that it's working well in yours.

Both of my barrels are 1:11" twist Krieger. Since you didn't mention moly, I'll assume you don't use it. That might affect things a bit, but there should be no case capacity problem.

Thanks!

 

[Steve Blair]

German,

My current F/TR load is Berger 210 BT-LR seated to 3.030 OAL, Lapua brass 55.7 g H2O, Wolf KVB-7, 46.6 RL17 for 2620-2630 from 30". My barrel is a 10" twist. I am working with the same load in my Eliseo prone gun but have not completed the series.

I have worked with the Sierra 190 and RL17 in the same rifle but could not get enough powder in the case to reach full pressure, necessary for RL17's best performance. The Sierra 190 touches at 2.989 OAL in that rifle. FWIW, my records show averages of 2714 fps and 19.4/7.7 ES/SD at 46.5 grains. All loads used 190 molys. I do not like to shoot any more than light compression, so it might be possible to force some more into the case but I have not found that very beneficial.

 

[Steve Blair]

In the lapua brass I have I can get 55.2 gr. of N550 in the case, but thats with a drop tube.

Should that read "45.2 grains"?

 

[TonyR]

I thought Palma was limited to bullets with 156gr maximum weight? In any event, I'd be interested in 308 loads for the 180-190gr bullets as well.

 

[GermanS1]

Tony, in NRA Palma matches, any bullet weight is permitted. This short article explains the basics of U.S. Palma shooting. http://riflemansjournal.blogspot.com/2010/08/shooting-events-palma-shooting-in-us.html

Steve, I tried RL17 some time ago and concluded the same thing you did, with a 190 it just isn't quite right. I think H4350 will be similar, so I am mostly thinking of N550 as the principal powder to try.

 

[GermanS1]

I just did a water capacity check on two pieces of the WCC 58 brass; they take 58.0 gr. of water right to the case mouth. Suprisingly, not that terribly different from the Lapua Steve checked at 55.7.

Empty brass weighs 150.2 gr. average.

 

[Steve Blair]

With the slight increase in powder capacity the Berger 210 provides (note the OAL in previous post) and increased bullet weight, RL17 produces fine results.

In going over my records, I cannot remember why I stopped 190 MK development. The log shows a long series of Sierra 155 and Berger 155.5 load development, maybe I just got distracted. I still have ~3500 190 molys and should probably resume development. In other rifles, IMR 4320 and H4895 were my old 190 standards.

Recent results with 8208 XBR and Berger 155.5 in Lapua Palma brass have been outstanding. My prone rifle is just over 3000 with some roundness on the CCI 450s at 45.6 grains. In a 31", 10" twist barrel, it is shooting .3-.4 MOA and ES 8-14. We have a short (300 yd) Palma on the 21st and I will shoot that load.

BTW, the Lapua lot I am using was sorted to 172.0-172.3.

 

[memilanuk]

German,

In the past I've used B190VLDs (and S190MKs) with RE15 with good results - MV in the 2600-2650 range from a 24" barrel.

I'm getting set to do some tinkering with B185LRBTs and B210LRBTs this fall... what powder to use seems to be the magic question. I know some people using Varget & H4895 with 185-190gr bullets, and some people using RE17 behind 208-210s. I've got some Varget, and a lot of N150. N550... not so sure I'm as keen on trying that stuff. I had been using it behind some B90VLDs in a .223, but it started get erratic as we moved into the heat of the afternoon - finally lost a bullet somewhere between the 900yd firing line and the target. A couple years ago a team mate lost a couple 155VLDs @ the SOA match in the late afternoon heat with N540... so for me Vihtavouri double-base powders are getting on that list of stuff I'm not in a hurry to buy more of.

Monte

 

[GermanS1]

Monte, when I was fooling with the 90 gr. VLD/.223 combination, I found N540 to be downright dangerous in the heat, but N550 was very stable. Since our season is a bit backwards and all of our Palma matches are in the cool months, I'm not overly concerned about the N550, but it does bear watching, you're right about that. If I get the basic chrono and load workup done now when it's well over 100 degrees, the load should be safe in the 45 to 70 degree fall/winter weather.

I have 2 lb. of N550 and a quick check on the internet shows that it's out of stock everywhere. So, unless a shipment comes in, this won't be much more than a theoretical exercise!

 

[uncleduke]

An often overlooked powder with heavy bullets is IMR 4007. 2650 is easy to reach with the 190's. I use it with 200smk's and no problems with heat issues. Just a thought.

 

[Laurie]

German, Monte,

N550 in stout loads is the norm in the UK for F/TR loads for 185s and above. Brass is invariably Lapua, so far all large primer variety so far as I've seen. I run the Berger 185 BT L-R at around 2,780 fps, but several guys are getting another 100-150 fps above that, and equivalents from the 210s, 2,650 to around 2,700 fps.

We rarely worry about very high temperatures here of course, the 80s being exceptionally hot and most summer matches shot in lower temperatures. People have tried other powders including Re17, but nobody has found anything better than N550 so far in our conditions for the heavier bullets. N540 is the most widely used for 155-175 gn bullets in F/TR, although Varget, H4895, Re15 and IMR-4064 have their proponents too.

In Target Rifle, (Fullbore Rifle to you guys) N140 is probably used by some 80-90% of shooters with their 155s, a few with N150 or the American powders, these being a lot dearer in the UK than Vihtavuori products.

Laurie,
York, England

PS I've now got my .223 F/TR shooting very well with 90gn Berger VLDs at a shade under 2,900 fps. In an 18lb F/TR rifle, recoil and torque effect on the bipod are negligible and it's a pleasure to shoot. I'll likely be using the .308 a lot less from now on.

 

[DukeDuke]

My best load was 49.5gr. of N550, 190 MK COL-2.950, mv 2890fps-2907fps out of a 30" 1-11" Krieger. Accuracy was superb out to 600y. Recoil was ok, I could spot the impacts through my scope at X30. Winchester brass and LR primers.

 

[GermanS1]

Duke, that's faster than I shoot 190's in my .30-06!

Laurie, thanks for chiming in, I had a notion that N550 was popular in the UK, for some reason I was thinkingof the MR shooters, but of course F-Class is growing quickly everywhere so that's more likely where the action is.

Your summer temperatures are roughly equal to our winter temperatures, hopefully that will keep the less pleasant characteristics of the powder at bay. If I can find a safe 2750 with the 190 VLD, I'll be more than satisfied.

 

[M700]

Observed some interesting, high velocity, results from IMR 4350 and Sierra 180's... More details sent via PM.

 

[Laurie]

for some reason I was thinkingof the MR shooters

German,

you were right on with that thought. The MR brigade discovered the utility of N550 way before we F/TR Johnnie-Come-Latelies did. That's largely because they understood all about heavy bullets at long range in the .308 years before F-Classers who've been busy reinventing the wheel in isolation. There's more of us F/TR shooters, we're more widely dispersed around the land (MR being heavily concentrated on Bisley while the F/TR heartland is the north of England with keen types spread everywhere); and we're a brasher, noisier crowd!

Until it was discovered within F/TR that the 185gn Berger BT Long-Range is hard to beat at any range to 1,000yd, a learning curve that I played some small part in promoting here, received wisdom was to shoot 155s very fast (up to 3,150 fps in some cases) over N540. A regular in the F/TR league match circuit George Barnard, who confines his entries to Bilsey matches really shocked a lot of the 155 users into rethinking this premise last year by how well his 200gn Sierra MR derived loads performed in a pre F-Class World Championship team training weekend in very rough conditions.

We saw wholesale rebarrelling to faster twist tubes here over the winter of 2009/10 amongst the top 20 F/TR league contenders. Experimentation with individual bullet weights and models continues, partly driven by bullet supply problems. The number of 185 Bergers on back order here must run into the tens of thousands now!

I intend to continue my tests with the .308 in the autumn using the whole gamut of 'heavies' from Berger, Hornady and Sierra, also trying Re17 and (as uncleduke suggests) IMR-4007SSC. I've been somewhat distracted by delivery of my .223 and working up 90gn loads in a hurry for the second half of the F-Class national league season. I did try 4007 in the mouse-gun cartridge and got good results, but at around 100 fps down on N550 or Re15 with a load that was already compressed.

Laurie,
York, England

 

[USSR]

Duke, that's faster than I shoot 190's in my .30-06!

German,

If you used 60.5 - 61.0 grains of RL22 in your '06, you could run them at 2900fps. Back to the .308 and 190SMK's. Have been using 47.0gr of N550 in Hornady Match brass for 8 years now. I get 2700fps out of my 26" barreled FN SPR. Forget H4350 - too slow. You won't even reach 2600fps with a case full of it.

Don

 

[GermanS1]

I shot the N550/ Berger 190 VLD moly combination today over the chrono. Working up from 44.0 grains at 2 shots per load increasing 0.5 gr. per load, I ended up at 2770 fps with the top load. I then loaded 10 shots of the top load and fired them to get a semi-useful SD number, it was 8.

Tomorrow I'll shoot a string of 20 at 500 yards in a match along with my two usual loads (190 Sierra 2660 with 4064 and 175 Berger at 2850 with H4895 both chronographed today also). We'll see how it does!

 

[memilanuk]

German, Laurie,

Do either of you have access to someone with pressure testing gear like RSI Pressure Trace?

A while back (about a year and a half) on another forum, one curious soul was testing his rifle while shooting some S190MKs over Viht N550 and recorded some rather disturbing traces showing a secondary pressure spike during the last quarter of the barrel time. The loads shot well and all, but there was a bit of speculation over whether a faster powder or heavier bullet was in order...

Here's one of recorded traces...

It'd be interesting to see if this phenomenon repeated across other weapons and ammo combinations...