How to reduce velocity spread?

S

supersonic

Guest
I use 6,5x55 Blaser for both hunting and target-sometimes long range target shooting. I use 139gr Lapua bullet and Accurate 3100powder and velocity is about 840m/s and velocity spread is up to 10m/s. I do not neck turn. I use Lapua cases. I debur the flash hole from inside. I reduced the velocity spread by using magnum primers,with benchrest primers it was even higher. Now I suspect powder..when I look closely at grains..some of them are shorter and some of them are twice as long as is some average length. Thinking about trying Viht 160. But it cost twice as much here. Could it help?
Thanks for any advice.
Best regards,
Petr
 
Supersonic
As you slowly increase your powder charge the extreme spread will drop then it will start getting larger again.
When it is at its minimum if its still too high for you swap out the primers first as they will give you the most improvement possible.
If its still too high change powders.
Lynn
 
Buy a decent electronic scale, $275-350USD, and weigh your charges to the individual powder kernel.

al
 
alinwa said:
Buy a decent electronic scale, $275-350USD, and weigh your charges to the individual powder kernel.

al
Click to expand...


I have mechanical scale-Dillon Prec. and I check the scale with the same weigh as I am weighing for every 8th cartridge. I think I could be very close to what you had wrote. Is not electronical scale mechanical inside too? I do not know,since I started to shoot after some years and my equipment might be obsolete now.Are all serious competitors using electronic scales nowadays?
Regards,Petr
 
You have to be able to see an individual kernel of powder, not a "grain" as in weight, a single kernel. My scale weighs to 00.00 grains. One of my loads is 40.04gr and my variance allowed is 40.02 to 40.04

IMO this will do more quicker than any other "fix."

Once I've got the weight dialed, THEN I play with other items, like primers or seat depth.

al

al
 
I use a Toledo lab scale, completely enclosed. It weighs to 0.0001 grams, or about 0.001 grains (have grams to grains conversion chart in Excel). My match loads are +/- 0.01 grains with the middle +/- 0.005 going to record loads and the high/low going to sighters (highs and lows not mixed during sight in). If I don't hit in the tolerance band, I scrap the powder weight run and start over. It is not too hard to get within my tolerance band with H4831SC and R25.

The same scale is used to "bucketize" bullets by weight for more uniformity after meplat trimming in lots of 1000 bullets.

Other big keys are uniform neck tension (annealing helps) and really good dies like Redding.

FWIW,

Jeff in OH
 
alinwa said:
You have to be able to see an individual kernel of powder, not a "grain" as in weight, a single kernel. My scale weighs to 00.00 grains. One of my loads is 40.04gr and my variance allowed is 40.02 to 40.04

IMO this will do more quicker than any other "fix."

Once I've got the weight dialed, THEN I play with other items, like primers or seat depth.

Hello,it was just my bad english,of course I ment kernel-did not relize the meaning of grain and confused A and B. I think I am able to stay inside -/+ 0,05grain.No better. But I was just counting this: Velocity with 9gbullet is 830m/s and energi is 3100J. When vel goes up to 831m/s ,than energi is 3107,5J. It means ,one meter per second variation gives 7,5J energi variation. You obtain 3100J from 48grain of powder. 3100:7,5= 413 48grain is my charge of powder. Now: 48gr of powder devide by 413 should give you the amount of powder "responsible" for 7,5J of energi in my cartridge and it is 0,116grain of powder. I know it could work otherwise and I should try to get better scale anyway. My friend has more than one a said non is keepind zero for too long and he must keep checking very often..
Regards,Petr
Click to expand...
 
Petr,

I weigh EVERY CHARGE..... Each and every load is weighed and checked. In my opinion no powder measuring device including the RCBS ChargeMaster is accurate enough for low Extreme Spread.

al
 
johnmethius.jpgPeter
You can get single digit extreme spreads with a RCBS 5-0-5 scale for $50.I have a 123 scale and it will measure down to a kernel but for single digits it isn't required.It would serve you well to have a decent scale but its not a must have for single digits.
Generaly as you work up a load while chronographing you will notice your extreme spreads dropping as you enter a node then increasing as you leave the node.I call it an hour glass shape as its big on both ends and small in the middle.

As an example we can look at a standard 6BR with a fed 205m primer.As you get past 2900fps your extreme spreads will be around 60 fps and as you increase your powder charge in 0.1 grain increments which is usually a 10 fps velocity increase your extreme spreads will drop.When you get around 2950-2970 fps velocity your extreme spreads will be around 20-25 fps with no regards placed on anything else.That means brass straight from the box as well as bullets straight from the box.
If you try and go past 2970 fps the primers will pierce on you.
If you then swap to CCI 450 Magnums instead and do the same incremental work up your extreme spread at 2950 - 2970 fps will be down around 8-10 fps.If you keep going higher than 2970 your extreme spreads will quickly hit 75 fps or more and you accuracy will also go away very quickly.
This can all be done with a relatively cheap scale.From there you can do other steps that will lower your extreme spread even further but the gains are not as drastic in my experience.
A local shooter at our club spent over $3000 on a Promethius set up but if it were my money I would make my own.
Lynn
 
Last edited:
Lynn said:
View attachment 10894Peter
You can get single digit extreme spreads with a RCBS 5-0-5 scale for $50.I have a 123 scale and it will measure down to a kernel but for single digits it isn't required.It would serve you well to have a decent scale but its not a must have for single digits.
Generaly as you work up a load while chronographing you will notice your extreme spreads dropping as you enter a node then increasing as you leave the node.I call it an hour glass shape as its big on both ends and small in the middle.

As an example we can look at a standard 6BR with a fed 205m primer.As you get past 2900fps your extreme spreads will be around 60 fps and as you increase your powder charge in 0.1 grain increments which is usually a 10 fps velocity increase your extreme spreads will drop.When you get around 2950-2970 fps velocity your extreme spreads will be around 20-25 fps with no regards placed on anything else.That means brass straight from the box as well as bullets straight from the box.
If you try and go past 2970 fps the primers will pierce on you.
If you then swap to CCI 450 Magnums instead and do the same incremental work up your extreme spread at 2950 - 2970 fps will be down around 8-10 fps.If you keep going higher than 2970 your extreme spreads will quickly hit 75 fps or more and you accuracy will also go away very quickly.
This can all be done with a relatively cheap scale.From there you can do other steps that will lower your extreme spread even further but the gains are not as drastic in my experience.
A local shooter at our club spent over $3000 on a Promethius set up but if it were my money I would make my own.
Lynn
Click to expand...

Dear sir, sometimes I was feeling ,that vel. spred had something to do with speed, but I was not sure.It is very interesting -your info. The only problem is,that I do not seat the bullets into the lands and for given charge I search for accuracy through setting the bullet at different depth /different COL. And sometimes when I reach a very good accuracy level at 1OOm,than vel spread is high. If I would add some powder,than accuracy is mostly quickly gone,since it depends on certain combination of COL and powder charge. Seems to me ,the only way would be to play with powder charge a vel spread at first and than to play with COL..?
Thanks for your advice.
Regards,Petr
 
Supersonic
Petr try this and let me know what you get.
Seat your bullets so closing the guns bolt pushes the bullet farther into the case.Write your COL down and do a powder work-up using a 1% increment and leaving your COL the same for all powder charges.
I think you will find that your smallest groups occur very closely with your lowest extreme spreads.Now adjust your COL until you get best accuracy.If your extreme spreads are still too high try a known colder and a known hotter primer than you are alrteady using and post back your results.The primer change will most likely show you which direction to go in.If it doesn't and you have tried all the known good primers for your combination its time to change your powder choice.
At 600/1000 you need your extreme spreads low enough to shoot winning groups.
I would give RE22,H4831 and H4831SC a try along with CCI BR2 primers
Lynn
 
Lynn said:
Supersonic
Petr try this and let me know what you get.
Seat your bullets so closing the guns bolt pushes the bullet farther into the case.Write your COL down and do a powder work-up using a 1% increment and leaving your COL the same for all powder charges.
I think you will find that your smallest groups occur very closely with your lowest extreme spreads.Now adjust your COL until you get best accuracy.If your extreme spreads are still too high try a known colder and a known hotter primer than you are alrteady using and post back your results.The primer change will most likely show you which direction to go in.If it doesn't and you have tried all the known good primers for your combination its time to change your powder choice.
At 600/1000 you need your extreme spreads low enough to shoot winning groups.
I would give RE22,H4831 and H4831SC a try along with CCI BR2 primers
Lynn
Click to expand...

Thanks a lot for your help. Now I play with my new barrel-I have two-one thin for hunting a silhouette and thicker new one for silhouette and target matches-contests. At the moment I am concentrating on 7g Lapua for hunting as well as for silhouette and for that I need to stay out off lands. The reason is,that it has happened to me in past severel times-when I loaded cartridge and I did not fire and wanted to remove not fired cartridge-than the bullet remained stucked inside and I remuved just case from inside.. That is why i would test ammo with bullets seated into the lands ,If I would plan to use it just for long range target mainly. And I am waiting now for over one week for new magnum primers for those heavy bullets. distributer I am buing from must be on his holyday or I do not know.. So far seems that my new barrel should be good. Yesterday I fired rather good group for factory rifle-not a heavy one-4,2kg with scope.I fired from bipod using the rear rest. 7g Lapua bullet,100m 5shots -0,3inch ,BUT the preassure was already too high-it means I must start again...,as I do not want to use that load. I was shooting 6,5 x 55 for long time in past and I managed to win several contests with it here in Czech. I was using kind of custom rifle with Krieger and Hart barrels. I sold it and I regret that a bit now, since I did the stock myself.. From my experience, Lapua 9g was getting the best groups when seated off tha lands but the velocity spread was high-remember 12m/s-but majority of contest was up to 500m so it did not matter that much. I was having good groups with Berger 140gr too ,but not as good as with Lapua and it had to be seated into the lands. Some very good results similar to Lapua-was with Clinch river 147gr bullet and it was also seated into the lands..but those bullets are no longer available to me. I notised that Berger started to produce new line of 6,5 140gr bullets which they call Long Range and I think that those bullets have exactly the same shape as those Clinch river 147gr which was perfect. So I plan to get them and than I WILL DO WHAT YOU JUST ADVICED ME. Than I will certainly write to you,but it may take some long time,since here in Czech it is not so quick to get things from USA Berger.By the way,what dou you think about the new Berger Long Range bullets? They have a bit lower BC compare to VLD, but they should give more consistent results perhaps?
Thanks and I will let you know sometime this year. Actuaaly ,where are you from?
Best regards,Petr
 
Petr,

You've been given good advice on the specific question you asked. Personally, I'm not quite so careful on weighing powder -- I throw a charge a little light, then trickle in a granule at a time on a good electronic scale, until adding that 1 more granule takes it to the desired weight. Then I use a second scale just to do a quality check. It goes faster than it sounds.

And as Lynn said, seating depth, along with neck tension, goes a long way to controlling velocity variations, as well as contributing to accuracy.

But before you weigh powder that carefully, it is best to do some testing to see just what components you will use. Here in the States we are blessed by having a large selection of powders, bullets, and primers. You may not have as many choices.

The best way to select is to shoot, say, three shot groups. If three shots are not so good, a fourth or fifth won't make things any better. The goal is to rule out things that don't work. If you are not comfortable with your shooting, use four shot groups - Again, the goal is to rule things out.

For example, with different barrels and powder, I've found that occasionally, primers matter. Usually not, so I sometimes forget to check. Bad. Take nothing for granted.

Once you have promising components -- bullet, primer, powder, then begin to dial in the load along the lines Lynn suggested -- specific charge weight, bullet into or off the lands -- and just how far -- and neck tension.

Things may change a bit with different temperatures, so keep notes.

Another thing unmentioned is that your dies need to match your chamber as closely as possible. Esp. your seating die if you are running the bullet into the lands. Often the amount of engagement is critical, and poor dies -- especially those that work off the tip of the bullet -- will give you a variation in the actual land engagement.

There is an old saying about accuracy reloading: "I do 10 things. I know only four matter, I just don't know which four." Now you might think that you could eliminate one of the 10 at a time to find out what matters, but it doesn't always work that way. Sometimes two things in concert give a good improvement, but using just one or the other shows no benefit.

As always, test for what your *rifle* likes, not what *you* like. And keep notes.

Good luck to you,

Charles
 
Supersonic
Petr if youi can get the Berger VLD's in Czech they like to be jammed into the lands and they also like to be Jumped a very long ways from the lands so they may fit into your magazine and still shoot well.I have seen them jumped 0.185 inch and shoot incedibly well at that distance.
Myself I prefer the VLD Hunting bullets for both hunting and target shooting.Berger sells 3 bullets now in most weights.One they call the VLD Hunting one they call VLD Target and one they call Long Range Target BT.The two VLD bullwets are the same except the Target version has a thicker jacket which you don't need unless your bullets are failing to reach the target.The Long Range Target BT bullets have a slightly different Ogive shape and are very easy to seat and get good accuracy with.They are very user friendly bullets.
I live in California in the good ol USA so I'm a long way from Czech.
Here is some data from www.hodgdon.com Once there you have to find the data which is not easy if your not used to our terminology.

Lynn
You can click on this link and get another 131 loads.
http://reloadersnest.com/query_all.asp?CaliberID=120


120 GR. NOS BT IMR IMR 7828 SSC .264" 3.000" 45.5 2590 40,200 CUP 49.5C 2802 45,600 CUP
120 GR. NOS BT Hodgdon H4831 .264" 3.000" 44.5 2528 36,200 CUP 49.5C 2802 45,900 CUP
120 GR. NOS BT Hodgdon Hybrid 100V .264" 3.000" 41.0 2553 39,300 CUP 45.5 2787 46,000 CUP
120 GR. NOS BT IMR IMR 4831 .264" 3.000" 44.5 2674 38,400 CUP 48.5C 2913 46,200 CUP
120 GR. NOS BT Hodgdon H4350 .264" 3.000" 41.5 2545 36,800 CUP 46.0 2792 45,800 CUP
120 GR. NOS BT Hodgdon H414 .264" 3.000" 40.0 2528 37,000 CUP 44.5 2783 46,000 CUP
120 GR. NOS BT IMR IMR 4350 .264" 3.000" 43.0 2631 39,500 CUP 46.8C 2863 46,000 CUP
120 GR. NOS BT Winchester 760 .264" 3.000" 40.0 2528 37,000 CUP 44.5 2783 46,000 CUP
120 GR. NOS BT IMR IMR 4007 SSC .264" 3.000" 41.0 2603 37,900 CUP 44.2 2788 45,100 CUP
120 GR. NOS BT Hodgdon H380 .264" 3.000" 40.0 2555 38,200 CUP 44.3 2784 46,000 CUP
120 GR. NOS BT Hodgdon Varget .264" 3.000" 35.0 2579 36,800 CUP 39.0 2812 45,300 CUP
120 GR. NOS BT IMR IMR 4064 .264" 3.000" 37.0 2625 41,300 CUP 40.0 2764 45,100 CUP
120 GR. NOS BT IMR IMR 4895 .264" 3.000" 36.0 2569 39,200 CUP 39.6 2767 45,900 CUP
120 GR. NOS BT Hodgdon H4895 .264" 3.000" 34.0 2571 43,000 CUP 37.8 2715 46,000 CUP
129 GR. HDY SP IMR IMR 7828 SSC .264" 2.935" 45.0 2537 38,900 CUP 49.0C* 2734 45,000 CUP
129 GR. HDY SP Hodgdon H4831 .264" 2.935" 44.0 2449 35,600 CUP 48.5C 2689 45,000 CUP
129 GR. HDY SP Hodgdon Hybrid 100V .264" 2.935" 41.0 2504 39,300 CUP 45.5 2743 46,400 CUP
129 GR. HDY SP IMR IMR 4831 .264" 2.935" 43.0 2549 37,200 CUP 47.0C 2792 45,100 CUP
129 GR. HDY SP Hodgdon H4350 .264" 2.935" 40.0 2430 35,100 CUP 45.5 2703 45,500 CUP
129 GR. HDY SP Hodgdon H414 .264" 2.935" 39.5 2460 37,900 CUP 43.5 2677 45,700 CUP
129 GR. HDY SP IMR IMR 4350 .264" 2.935" 42.0 2584 40,000 CUP 46.0 2793 45,800 CUP
129 GR. HDY SP Winchester 760 .264" 2.935" 39.5 2460 37,900 CUP 43.5 2677 45,700 CUP
129 GR. HDY SP IMR IMR 4007 SSC .264" 2.935" 40.0 2548 39,000 CUP 43.4 2718 45,600 CUP
129 GR. HDY SP Hodgdon H380 .264" 2.935" 38.5 2440 38,400 CUP 42.5 2654 45,500 CUP
129 GR. HDY SP Hodgdon Varget .264" 2.935" 34.0 2472 36,900 CUP 37.5 2664 46,000 CUP
129 GR. HDY SP IMR IMR 4064 .264" 2.935" 36.0 2534 39,800 CUP 39.2 2704 45,800 CUP
129 GR. HDY SP IMR IMR 4895 .264" 2.935" 35.0 2488 38,400 CUP 39.0 2703 45,600 CUP
129 GR. HDY SP Hodgdon H4895 .264" 2.935" 33.0 2373 38,200 CUP 36.3 2561 45,600 CUP
140 GR. SPR SP Hodgdon H1000 .264" 3.030" 46.5 2423 37,600 CUP 51.5C 2651 46,000 CUP
140 GR. SPR SP IMR IMR 7828 SSC .264" 3.030" 44.0 2460 38,300 CUP 48.2 2678 45,800 CUP
140 GR. SPR SP Winchester Supreme 780 .264" 3.030" 45.0 2451 40,600 CUP 47.8 2592 45,300 CUP
140 GR. SPR SP Hodgdon H4831 .264" 3.030" 42.5 2382 38,100 CUP 47.0 2586 45,700 CUP
140 GR. SPR SP Hodgdon Hybrid 100V .264" 3.030" 40.0 2418 38,300 CUP 44.5 2642 45,200 CUP
140 GR. SPR SP IMR IMR 4831 .264" 3.030" 43.0 2507 39,100 CUP 46.3 2700 45,400 CUP
140 GR. SPR SP Hodgdon H4350 .264" 3.030" 39.5 2418 38,600 CUP 44.0 2617 45,700 CUP
140 GR. SPR SP Hodgdon H414 .264" 3.030" 37.5 2393 40,000 CUP 41.5 2565 45,600 CUP
140 GR. SPR SP IMR IMR 4350 .264" 3.030" 41.0 2486 39,300 CUP 45.0 2677 46,000 CUP
140 GR. SPR SP Winchester 760 .264" 3.030" 37.5 2393 40,000 CUP 41.5 2565 45,600 CUP
140 GR. SPR SP IMR IMR 4007 SSC .264" 3.030" 39.0 2400 38,600 CUP 42.8 2591 45,300 CUP
140 GR. SPR SP Hodgdon H380 .264" 3.030" 36.5 2316 37,600 CUP 40.5 2520 45,100 CUP
140 GR. SPR SP Hodgdon Varget .264" 3.030" 32.5 2312 37,500 CUP 36.0 2528 46,000 CUP
140 GR. SPR SP IMR IMR 4064 .264" 3.030" 35.0 2394 39,500 CUP 38.0 2563 45,800 CUP
140 GR. SPR SP IMR IMR 4895 .264" 3.030" 34.5 2364 38,900 CUP 37.8 2550 45,500 CUP
140 GR. SPR SP Hodgdon H4895 .264" 3.030" 32.5 2305 38,100 CUP 35.8 2493 45,700 CUP
142 GR. SIE HPBT Hodgdon H1000 .264" 3.050" 48.0 2453 37,500 CUP 51.5C 2601 41,600 CUP
142 GR. SIE HPBT IMR IMR 7828 SSC 264" 3.050" 44.0 2457 38,600 CUP 47.7 2671 45,500 CUP
142 GR. SIE HPBT Winchester Supreme 780 .264" 3.050" 44.6 2461 41,100 CUP 47.5 2640 45,900 CUP
142 GR. SIE HPBT Hodgdon H4831 .264" 3.050" 42.5 2383 37,300 CUP 47.0 2604 45,300 CUP
142 GR. SIE HPBT Hodgdon Hybrid 100V .264" 3.050" 40.0 2420 39,300 CUP 44.0 2658 46,200 CUP
142 GR. SIE HPBT IMR IMR 4831 .264" 3.050" 43.0 2500 38,400 CUP 46.5 2704 44,900 CUP
142 GR. SIE HPBT Hodgdon H4350 .264" 3.050" 39.0 2427 38,400 CUP 43.7 2653 45,800 CUP
142 GR. SIE HPBT Hodgdon H414 .264" 3.050" 39.0 2399 37,200 CUP 43.0 2653 45,300 CUP
142 GR. SIE HPBT IMR IMR 4350 .264" 3.050" 41.0 2452 38,000 CUP 44.8 2667 45,100 CUP
142 GR. SIE HPBT Winchester 760 .264" 3.050" 39.0 2399 37,200 CUP 43.0 2653 45,300 CUP
142 GR. SIE HPBT IMR IMR 4007 SSC .264" 3.050" 39.0 2441 38,400 CUP 42.8 2638 45,900 CUP
142 GR. SIE HPBT Hodgdon H380 .264" 3.050" 35.0 2239 35,600 CUP 38.5 2437 45,300 CUP
142 GR. SIE HPBT Hodgdon Varget .264" 3.050" 34.0 2334 38,100 CUP 38.0 2559 45,700 CUP
142 GR. SIE HPBT IMR IMR 4064 .264" 3.050" 35.0 2430 40,300 CUP 38.0 2582 45,600 CUP
142 GR. SIE HPBT IMR IMR 4895 .264" 3.050" 35.0 2416 40,000 CUP 38.3 2574 45,700 CUP
142 GR. SIE HPBT Hodgdon H4895 .264" 3.050" 32.5 2311 37,800 CUP 35.8 2511 45,800 CUP
 
Last edited:
You must log in or register to reply here.
Back
Top