.308 home loads

[Richiew]

Hi all first post so go easy

 

 

rifle is accuracy int At 308 with 1 in 12 twist 26" barrel , started with ppu ammo and got 2" groups at 100 m , not impressed !!. changed to hornady factory ammo 155 amax and 168 gr hpbt and got much better groups but still not as expected .moved onto home loading with viht n135 powder starting at 39 gr and moving up in.5 jumps to 43 grs using the hornady cases and lapua 155gr scenars and 155 amax s . getting good results now with a sweet spot with both bullets at 42.5 gr and 2.8 " coal .75 " groups .still not happy so moved the seating depth around and got a hornady length gauge to measure cbto .

 

berger fullbore 2.2" cbto coal 2.889

lapua scenar l 2.243 cbto coal 2.842

Amax 2.223 cbto coal 2.845

sierra tmk 2.223 cbto coal 2.94

 

All above 155 gr apart from berger 155.5 s .

 

 

 

 

accuracy has improved dramatically with best being berger fullbores at a 5 shot group with 3 through same hole and another two touching - less than 12mm ,. also 10 shots through hole less than a thumb nail .

Amax s are second best and are less finicky in seating depth also cheaper .

 

some of the seating depths seemed a tad too short so moved to 2.85 coal with the bergers and had 5mm of bullet in the case

now all at 2.85 coal - amaxcbto 2.225, scenar l cbto 2.250 ,sierra tmk 2.135 cbto ,berger 2.249 cbto

 

Happy days now with small groups less than .5" for 10 shots if I keep my cool and stay consistent at 100m

 

 

cases neck sized only, now onto Lapua brass, and primers are whatever is available ( cci / fiocchi )

 

hope this helps any new boys cheers

 

[duey]

I would try N140 & N150 behind the 155 scenars

I usually find best seating depth at 10 thou off the lands with scenars

i have had rifles in the past that worked best with46gr N140 but saying that my current 308 preferres 44 gr

 

I would suggest you try the slower powders and see how you get on

I think the current manufacture max loading for 155 scenars with N140 is about 44 gr so work any loads up slowly in no more than .2 gr increments

[snakeman]

Comparison for the 155TMK

 

 

Using 43.7g of N140 and CCI standard primer

 

 

Bullet only measurement.. B/O = 0.447

 

COAL (on measuring ogive at lands) = 2.994

 

CBTO (on measuring ogive at lands) = 2.177....(average of 12 tests)

 

COAL (after seating, and of accurate round, following a very finicky process finding the sweet spot) = 2.875

 

I seat CBTO = 2.050

 

 

So yes, 127thou...give or a take a thou or 2, seated off the lands...

 

Speed = faster than I can see...but bloody accurate

 

ATB

 

N.B... to assist other users of this bullet; If you attempt seating this at 2.800 COAL, you will likely find you're seating the ogive too deep in to the neck; you lose the ogive

[Richiew]

Hi All

thanks for the posts , tried to get close to the lands but closest I could get was 20 thou off and only about 2mm of bullet in the neck ,some of the shorter bullets were not even going to be in the neck !! so settled for coal of 2.95 also tried 2.9 . was going to try to find a sweet spot by moving 25 thou at a time ie 2.8 coal then 2.825 ,2.850 ,2.875 etc to find a good group then a little more fine tuning .might try the new hornady eld match as a replacement for the amax's .will try the n140 when my supplies run low as it should be good for 175's too .

thanks snakeman will try the 2.875 length next reloading session as i went straight down to 2.85 ,

tmks pointy bit are quite blunt compared to amax , is there any gain to be had from pointing the scenars ??

 

many thanks Richie

[snakeman]

Richiew

 

Although N140 will work with the 175g, you'll likely achieve better results with N150 with that weight bullet. ...(at least it does for me, when I use the 175g)

 

Don't underestimate N150 with the 155g bullet either; that too is a good combo..However, for your 155g bullet, N140, Varget, IMR 4064 and RL15 you'll find are probably best suited

 

ATB

[deadcenter]

I also use N140 for the 155's, N150 for heavier - 167/168's, 175's, even 190's.

[gbal]

Richie,thanks for a clear post.As Snakeman and deadcenter, V140 for 155 ,and V150 for heavier are usually good options-and available (many US powders may not pass the incoming REACH safety regulations).Bullets-a good lesson there too-quality pays off-Berger are usually excellent when you find the one your barrel likes best.Lapua are very consistent,and a less pricey option.Amax might be going...though replaced with ELD-guess what happens to the price!

But if you are getting well sub .5 moa for 10 shots,I'd not rush to change that load-V135 is ,(like all Vihtavuori) excellent powder (I use it in a 308x 1.5 Barnes (30 BR),with 125g bullets (shoots in the .2s).It's maybe a tad fast for typical 3o8w but it's working fine....,not broke.....

As you know,throating etc varies,so as ever,it's find what works in your particular rifle;And of course adequate bullet tension -as you mention...you don't want a bullet stuck in lands spilling powder into that action (rugged though it may be).

I would suggest you check grouping at longer distance if you intend to shoot at substantially longer range,to check velocities etc are adequate to maintain performance (or check with a magnetospeed). All sounds pretty good though.Enjoy!

 

gbal

[Richiew]

Hi gbal

Thanks for the info , the Bergers seem good and have a very small hole at the point.this hole looks to be filled poss with a glue? As some has spilled out making the bullets a bit tarnished an not too pretty but as results show very good at 100 m. Need to get get out to 300 m and buy a magneto too ,Catterick ranges are usually 100 m and sometimes 200 depending on what we are allowed ,300 m depends on weather ie if we can see the target fig11 s. Looking forward to some good autumnal weather

 

Cheers rich

[alpha1]

What does CBTO stand for.

[MrCetrizine]

Cartridge base to ogive.

[alpha1]

Thanks.

[VarmLR]

In many factory sporting rifles, you'll find that the throat dimensions are too long for loading close to the lands as they're chambered to accept a wide variety of (jump tolerant) hunting ammo, loaded to magazine length. It's not especially a great idea to try and load bullets out as far as they'll go in such chambers, but probably best sticking to magazine length at least for shorter bullets like most 150's etc. T3's in .308 for example have about 50 thou jump when loaded to magazine with 155 SMKs. There's the issue if inconsistent neck tension if loading too far out, and other stability/concentricity concerns which is why rule of thumb is to load at least one bullet diameter length into the neck, or at the very least, half a diameter for cases where the neck is proven concentric and neck tension consistent between cases. Otherwise results can be a little hit and miss. You'll still get good results when developing loads but are more constrained to jump tolerant designs, so the older #2155 will suit such chambers much better than the higher BC, newer #2156 for example.

 

For longer bullets such as the 190, it's not an issue. As mentioned above, whilst you can (and I have with some success) shoot the heavies using N140, N150 is much better suited, won't generate the same pressure spikes, should offer better consistency and even slightly better velocities. Reload Swiss RS50 is probably the better all-round powder which seems to do well with the heavier as well as lighter bullets in .308, exhibiting less pressure and better velocities than the Vhit equivalents (N140/150).

 

There is an answer for the chamber issues which is to have a competent gunsmith simply machine the chamber dimensions down a little to reduce the throat length to accept the (range) of bullets that you wish to load for, loading closer to the lands. You still have the option of loading to mag length. I intend on doing this if my 6.5 purchase happens to be a Swede rather than CM.

[gbal]

Rich,I'd not rush to get a magnetospeed,though £200 is "only" 4 boxes of Bergers! If you are shooting to 200,or 300 then 'holes on target' are a good enough guide....generally rifles shoot MV close enough-at those distances- to what the (vihtavuori) data gives for loads with the powder (if it has 135/155 !)..but you can get fair idea from bullet drop .....and aanyhow,if those are for now your ranges,it's a simple click up whatever the drop. A chrono does become useful if doing more detailed testing/variety of loads/powders /etc...but it has to be a good one (Mag/lab radar-pricey!). And for Long Range work-where velocity becomes more critical-as does BC,but to 2/300 these are minor (given reasonable values.)

Bergersare typically pristine from the box-with rather uniform 'hples'-meplets(in part a legacy of how the bullet is made.But not a big deal-afficionados sometimes meplet trim and repoint,but about half become dis-afficionados,asthere is very little on target return-especially out where the wind blows,and it's very had to tell...I'd rather have discoloured Bergers than shiny other makes-though Lapuaand Sierra are pretty good.Most attempts to improve good/custom bullets are counterproductive-no need to fill the meplet etc-just upsets the dynamics.

 

Alpha,CBTO is a far more consistent measure-needing a special (£30) tool,for seating depth work-because the ogive is far more consistent,than the length in many bullets -so COAL is crucial for magazine fit,but rather poor for \bullet jump'/seating depth from lands-it just varies a tad for bullets otherwise loaded identically. It's a detail for fine tuning max precision loads...Berger Bullets article by Bryan Litz explains well...CBTO versus COAL in a couple of pages,well worth a google.

 

...and yes,Bergers tend to be more uniform.

 

Good shooting,detailed or not!

 

gbal

[Richiew]

Thanks for all the replies ,theres lots of info to take in so maybe leave the chrono and borrow one next time at the range just to get an idea how fast we are .going to play with the seating depth and stick with the best load . have read the berger reloading manual and am working with different seating depths to find the best load then enjoy shooting small groups . Need lots of practice yet especially with the wind reading . think its Wathgill in October so would like a calm day.

Cheers for the info much appreciated.

 

Regards Rich

 

ps any ideas re cleaning the sealed Accuracy Int Moderator ?

[Richiew]

Just got back from Deerpark at Catterick today  10mph crosswind , rain then sun ie the usual mix . As before the Berger 155.5 were the best grouping 0.5 moa second best Amaxes , equal 3rd Lapua L and the Sierra TMK , lastly the Lapua scenars even though still at .75 moa . All seated at 2.85 COAL  ,150 bullets down range -a great day . 50 bergers left over so reseated these to 2.825 to try next time .Forster die was set up for a zero point of 2.85 coal so was just a matter of turning the knob one turn down which seats 25 thou deeper and hey presto job done . Looking back on previous results the 155 amaxes were the previous best groups at < .5 moa when seated at 2.800 coal as per Hornady manual .  All groups 5 shot and the ones that were very good kept going till had a ragged hole with 10 shots through .5 moa . only allowed 100m today so well happy .

rifle now cleaned and chilling with a beer            cheers all    

[Richiew]

Latest load for 185 Berger juggernaut 41.5 gr N550 great results less than thumb nail size groups at 100 m  at cow park 6a range at wathgill . Started from 41 and worked up to 46 grains , there was some good results at 44.5 but started to see marks on the case head . So now have loads for 155,175,185 burgers ,also 155, 168 Amax , lapua 155 standard and L scenars . Only need to get  them chrono ‘d and bobs your uncle . Cheers