6.5x47 Lapua Load development updated

[craig6547]

just an update on my load development for my new 6.5x47 build. 1st tests looked promising and then i made a mistake by adjusting seating depth too far without finding the node 1st. That lot of results were useless. Next stage i re done all tests with a .020" jump, again tests resulted in rubbish groups. As a last resort i checked scope ring screws thinking that theres no way it could be that.........well it was, they worked loose !!! Got them tightened up and more test rounds made up and got out today. here is a pic of the results.

Im thinking i will play with seating depths at 41.4gn charge ? what does everyone else think ?





craig

 

[craig6547]

All ive got for testing is my bipod and a rear bean bag, its pretty steady and its the same method i used for my old .223.

Bullet is 140GN A-Max, Reloader 17 and CCI 450 primers

 

[craig6547]

sorry forgot to add that detail in last post, im shooting prone.

 

[craig6547]

no offence taken at all my friend, you very well maybe right here and maybe something i am unaware i am doing.

 

[ShootDots]

I believe because you are NOT shooting from a bench, there are "hold" errors, or at least from the pic of the groups it appears so.. 41.1 has great e.s.'s... I would try that load again from the bench sans any changes... If it does not print better, try differing the seating depth.. I would also do the same thing with 41.4 to see if you could reduce the vertical dispersion as well as the e.s.'s... If you could do that with 41.4 you found your load!! But look at how close the vertical dispersion is on 41.1>>> I think there is shooter error there due to not being on a bench... Both groups need re-visitation..

 

[craig6547]

ShootingDots :-

That's exactly what I will do then. I'll make up more of both and see if I can get them printing better. I agree with you about. 41.1 load and with the ES as low as it is, that would be an ideal load to use. I also agree about shooter error with hold. Sometimes I do feel that I could have shot that group better which would defo be down to not having a 100% stable platform.


Craig

 

[ShootDots]

Craig, do whatever it takes to shoot from a bench that is steady >> not from bipods.. They can be steady with MUCH experience>>>>benches "generally" are steady from the get-go... I believe that the 41.1 load with the "high left" looks like shooter error. The other 2 have GREAT vertical but the high one does not represent the 9ft e.s.>>that's why I think it may be shooter error. In any event, please let us know what takes place with your further testing.. I would like to see how our "interpretation" of the groups stands... Thanks Craig!

 

[Erik Cortina]

As others have noted, groups are insonsistent.

41.1 has good ES, but look at the loads on each side of it, they are 20 and 19.

Based on ES only, I would play with 41.1 and see what that gets you. Shrink group as much as you can with seating depth and the go back and do powder charge testing in .1 increments from 40.8-41.7

Shooting from a bench is never more steady than shooting from the ground. What I would suggest you do is to shoot from a front rest if at all possible.

Good luck and keep us posted.

 

[Drop Port]

Are you shooting prone, or sitting at a bench, etc...?
Reason asking you these things, is I see possibility of movement (primarily based from the POI shifts between the sets).

In any regards, the 41.4 looks the best, and agree to continue from there....
Donovan

Not asking to be an ass just to understand, do you shoot prone all the time? Can you shoot 1/4 moa groups prone with other capable rifles. Was the surface hard or frozen? I ask this because I mainly shoot prone and I'm seeing things that stand out as operator error. I don't know how you shoot so it might not be you at all. 40.5 is a nice flat group and if the left one could have been you its worth revisiting. What concerns me is a .3 charge increase changed the whole shape of the group. I loaded for one that did the same thing with R-17 switched to H4350 and every load was decent. Also didn't jump the A Max that much they tightened up close to the land 3-7 thou off range.
When it comes to the bipod you can shoot bug holes but everything has to be consistent, grip, cheek weld, hard hold, soft hold, load or don't load the pod etc.

 

[craig6547]

Yeah I shoot prone all the time. My old .223 rifle I could shoot 1/4 MOA groups all day, best group I got with that rifle was 5 shot group at 100 yards producing 0.274" , basically through same hole.

I can't do much about powder I'm afraid, I know that H4350 is what I need but it's not in the UK at all.


Today I made up charges of 41.1 & 41.4 both with .003" increments closer to the lands from a .020" jump to .002" from the lands. Hopefully the weather will be ok 2moro so I can get out.

I feel that the reason that I am struggling is just down to shooter error. I was without my rifle for a while when it was getting built, so I feel I may have lost my touch and need to regain it.

Ill post results when I get out and test these rounds.

 

[craig6547]

Update on the load development guys:

I got hold of a dvd the other day, Long range precision shooting by Todd Hodnet from a friend of mine but i hadnt had a chance to watch it......until last night. I cant believe how much my shooting was to error. Loading the bipod...never even heard of that before and tried it today and with goes results. Shooting position was off aswell. The way i was gripping the pistol grip on the AICS was probably making me pull the rifle over by squeezing my finger and thumb together on the pistol grip. This time i kept the grip to the outside, pretty much the way i used to shoot the .223 when i had a Bell & Carlson Tactical stock on it.

Here is a pic of the group i shot today with 41.4gn charge seated with a .020" jump and same charge with a .017" jump.

Only problem is........I had to use new brass as im still waiting on my Redding FL Bushing Die getting delivered so i cant resize my fired brass. I do have a Forster FL die but there is a problem with it and its scratching my brass. I got hold of a neck sizer but the shoulders need bumped back cos i cant close the bolt with neck sized cases. Thats why i had to use new brass today. New brass neck size measures .287" . My neck sized and FL necks measure .289" so i had an extra .002" neck tension today with the new brass and straight away i ran into pressure signs, stiff bolt to open and plunger marks on the case head when i didnt have that with fired cases. Obviously the extra .002" is producing too much pressure. What can i do here ? The ES wasnt as good as it was in previous test with neck sized cases.

I also tested the 41.1 gn charge as suggested in previous posts. These ran into pressure signs straight away also, ES wasnt as good as previous test but better than 41.4gn charge.

41.4 gn charge:

2.800" jam -.020" : 2759, 2787, 2753
ES : 34
AS : 2766

2.803 " jam -.017" : 2769, 2796, 2809
ES : 40
AS : 2791

2.806 " jam -.014" : 2788, 2798, 2777
ES : 21
AS: 2787

Group for 2.806" was around .5" , never got a picture as it wasnt as good as these 2, but ES was better !!! it was the same POI as 2.803"

 

[craig6547]

Donovan :

Thanks for the encouraging words there. I will post more results when I get more tested. Hoping to produce more groups like these.



Craig