Best way to reduce ES?

[MJR]

As the title reads really. I batch weigh my brass (Sako .243), trim all the brass to same length,debur the primer hole, even all the primer recessess,weigh each charge but i'm still getting a velocity spread of 50fps. I'm using cci br primers and H4350 with 87gn Hornady bthp. This is with a std factory Tikka 595 sporter. Accuracy wise its 1/2 moa at 100yds but i'd like to reduce the spread before extending my range beyond 250yds. What can I do?

[1967spud]

how about teaking load and trying another primer

[MJR]

Tried Remmy 91/2 LR primers and they are no better.

[1967spud]

are you neck sizing if o how much tension you useing

[nemasis243]

Have a similar thing with my 243 but im running 58grners through it, there running with a 42ft p/s spread ,like you wieghed cases and also tried different primers , the only thing I can put it down to is a couple of thou difference that I get when seating, I can shoot bug hole groups with it so didnt bother chasing it any further,

Also have you ever tried wieghing the heads, I have and there is a slight difference,but nothing OTT.

[baldie]

Try federal gold medal match primers, or even a cci magnum primer. Providing your loads aren,t too hot, you should get away with a std primer. Also , if you are using bushing neck dies, try going to the next tightest bush on the neck.

[Ronin]

Ive found some powders suffer from larger ES than others.

 

H4350 is one of them.

 

I used to use it in my 6.5x284, now I use 4831SC.

 

ES has dropped from 30 to 20 with the load I use with 130 TSX.

 

 

Similarly I get ES in single digits with RL25 in my 7mm/270 WSM.

 

 

Case prep is the key, as is meticulous powder weighing and BR primers (CCI or Fed)

 

Powder I measured in Harrel then trickled up on digital scale to +/- .02grain......

 

 

 

Time consuming but worthwhile, especially if pushing the range.

[MJR]

Thanks for the replys guys. I have neck turned the cases just enough to true them up and i'm neck sizing with a Redding Type S neck die to 2 thou undersize. Am I right in thinking thats the correct 'grip' for the bullets? Could annealing them be the answer?

[MJR]

That could be one of my problems - i'm using an electronic scale which always seems repeatable but I don't have anything to measure it against. I throw a charge with a rcbs measure then trickle up to weight on the hornady scales..........

[Elwood]

Neck tension is definately one area to look at. My load for my 7WSM had an ES of 25 fps, I dropped down from a .308 bushing to a .307 bushing and then a .306 bushing. The .306 bushing gave me a ES of 14 fps, it did however lower my velocity from 3007 to 2976 fps but the group sizes shrank by 1/3 rd so all was well.

[Ronin]

I was fortunate to find some Acculab scales at reasonable cost.

 

Interesting point Ian re neck tension, I also use .306" bushing for a .312"nk WSM.

 

Checked last week, was running 10 shot ES in single digits,,,,,despite "warm" load.

[brown dog]

Reloading geekdom is a bit off piste for me so don't know enough to comment on powder and primer changes, but presumably you are weight sorting the bullets?

 

I'd also be interested in knowing how uniform the hornady bullets are before keeping them 'in' as the one unchanged ingredient. ie not just weight, but variation in diameter and bearing surface etc.

 

Just thinking out loud

[MJR]

No I haven't weight batched the bullets at all so that will be interesting. The neck tension is something I will be looking at as well.

[menial 1]

I've found the Hornady bullets to be all over the place weight and length wise. A few years ago it was .224 v-max that had quite large variations and now I find two of my other favourites have quite large variations (105gr 6mm Amax and 155gr .308 Amax).

Even bullets from the same batch numbers vary greatly and with the price increases recently it may well be time to look elsewhere.

I use Viht 133 and 140 in the 6BR and 160 in .243AI and find they don't cause me to have to tweak my loads too much from batch to batch.

Pete.

[Vermincinerator]

Get a 6MM BR

Pete, I got the spreads down to 11fps using Vit 135 with that Cooper you have now but noticed that they were not the most accurate groupers at 100yds.

 

Ian.

[menial 1]

Get a 6MM BR

Pete, I got the spreads down to 11fps using Vit 135 with that Cooper you have now but noticed that they were not the most accurate groupers at 100yds.

 

Ian.

 

Is this some sort of anomaly, with other rifles the spreads can be up 50fps for the best groups.

Or is it more a case of lack of consistency in my shooting tecnique?

Pete.

[MJR]

Well I weight a new box full of 87gn bpht and founda spread of 0.4gns from 86.9 to 87.3. To my reckoning thats a spread of .47%. How much velocity difference is that likely to make?

[Elwood]

How far past 250 yards are you going to be shooting?

 

Here's two sets of figures that I have run through Quickload using two different velocities 50 fps apart.

 

The data I'm using is from my 6BR load using 105 gr Scenars

 

At 2822 fps

 

Bullet drop is 7.1 inches at 300 yards

and at 1000 yards it's 306.7 inches

 

At 2872 fps

 

Bullet drop is 6.8 inches

and 1000 yards it's 294 inches

 

So the difference is 1/3rd of an inch at 300 yards and a whopping 12 3/4 inches at 1000 yards.

 

Now I begin to see why ES is so important at 1000 yards.

[Tikka 260]

FWIW

 

.... and I hasten to add that I am NOT a long range shooter by any manner of means, but the loads that I am using now in the .260 with Nosler 120 BTs, Nosler Custom Brass, Federal GM210M primers and 40.0 Gns of RL15, give me exactly what it says in the Nosler book, 2895 fps with 9fps ES , and they group .3MOA if I do my bit. Oh, its a Shilen Match barrel ..... 22" long from bolt face to crown and the bullets are seated at .030" off the lands; I put it down to the Nosler Custom Brass mainly, as thats the only thing I have changed recently apart from shortening the barrel down from 26".

 

I don't neck turn as the benefits for a stalking rifle seem a bit nebulous to me, and the neck tension is what it is ....... but then I am probably wrong about that All I know is that Fallow really don't like it !

 

Good luck with your researches.

 

Peter

[MJR]

How far past 250 yards are you going to be shooting?

Good question. My longest shot so far has been a crow at 276yds - not long at all by some standards and when i'm deer stalking I don't take long shots at all, most are 100 yds or less. BUT I want to extend my Target/varmint shooting distances and remain accurate and the more I get into reloading the more interesting I find it.

Another question, when using a neck sizing die is it best to just use the bushing on its own or the expander as well?

[Ronin]

Expander - throw away or turn down to it doesn't touch case.

[skany]

how long a string should u shoot for a ES test

 

I had 8 shots over the chrono with my 308 on monday for a ES of 13fps

 

I was fairly chuffed with this as its lee collet neck sized with nothing batched or weighed case or bullet wise!

 

lapua brass

fed gm2

155g amax's

44.5g of vit 150

cheers Andy