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ronzi83

After barrel cleaning groups

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Hello, i would like to ask you if this is normal groups after barrel cleaning ? I shoot 600 rounds and never cleaned gun and now i clean it and got this kind of groups when testing for new powder. I measured speed (only 2) for each load and than shoot 5 groups of 5 shoots. 

.338LM with rs80, 3.681oal starting from 92-96 grains

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distance?  I'm guessing 100m?

As your asking, I'm guessing they are not what you expected and looser groups than normal?

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Hi,

I have witnessed this behaviour on a couple of rifles (a P14 and my own 308), typically it should settle down within 20 rounds.

Please let us know if things settle down and after how many rounds.

Interestingly if you follow Mark and Sam after work, he only typically removes the carbon and patches through with some oil. Never copper defouls.

HTH 

G

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I clean my barrel after very shoot.  When I start load develop the round count would be in single figures.

SD from two shots is largely irrelevant, it could be significantly worse in reality.  Assuming the shots are otherwise well controlled I would say you need to find an accuracy node.

Also try half grain increments.

 

 

 

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Ronzi, do you do all five shots of each load and then on to the next set?

A few people (myself included) start at the lowest load on target 1 then next increment on Target 2 all the way up until you reach the highest load and then come back down accordingly and repeat until finished. The net effect is that you place all your shots (e.g. 90.5 grains load) on target 1 and (e.g 91 grains load) on target 2 (hope that makes sense?). This method distributes any temp variation.

In addition to this waiting a minute between each shot  allows yourself and the rifle to settle in to the groove and get good form for shooting. It does take a while though!

 

All the best

G

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I mostly did shoot each group than wait. Only for 92 group i shoot 2 shoots (1st 2) and i shoot another 3 on end. Because i saw 2 shoots really spread and i thought will be bad so i left 3 shoots for end. Mayby i will try 91.5 grains to see. But for long range do i seak accuracy or better sd ? Cose it may be good at 100m and bad at 1000m 

 

Regards

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Don't worry about SD too much just get what you want on paper and go with it. It doesn't matter what the figures say there's only one place where it counts - at the target.

It is very difficult to get an accurate SD with only 2 shots and my chrono will not even try to calculate it until I have a minimum of 3 shots.

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shoot groups nice and steady.  I don't agree with gruntus's method, I shoot 3 shots of one load spec and see what group I get.  Repeat for other loads.  Select the best three-shot group results and then shoot 5 shot groups to see what the best of this refined group result is. Then try slight powder weight variations on load around that best result.

SD is useful but it's irrelevant if the group is poor.

 

 

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It could be that you need to build the copper up again as gruntus states.

If you’ve never tested RS80 before, It could be that your barrel doesn’t like it.

As stated before, you should shoot OCW groups in a round-robin style to even out potential issues fatigue, position etc.

What you need to look for is the central node of a few groups, not chase small SD/ES. Find the three consecutive groups that all appear similar in size, are the smallest and display lowest vertical. So if you shoot 6 groups in total and find groups 4, 5 and 6 are all very similar and you’re happy with the size of groups, somewhere around the middle (group 5) will be the one to choose. This displays stability and predictability. Then tune the load and tighten the group size by adjusting seating depth. You could experiment with 0.1gn or 0.2gn charges either side of your optimum charge to fine tune it further. Up to you.

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0.1 grain in .338LM is nothing mate. It is not 6.5 creed that you would do load by 0.2 or 0.3 grain increasment. Even so a good node lets say 43 grains (6.5creed) can shoot good  between 42.8 and 43.3. What i want to say is that in 338 load 0.5 grain will have min effect and if node it 92 it will shoot also at 91, alteast not really THAT huge group open. I can start 89 up to 97 but min i would go is by 0.5 grains. Yes i never shoot RS80. I was using N570.  But i cleaned totally barrel and i will test next time 91.5 , 96.5 and 97   

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half grain increments is sensible for .338 as you say.

N570 is excellent.

Don't understand the logic for round-robin groups - introduces too many other variables in my opinion.

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No, round robin is the correct way to OCW.

Also, my comment about 0.1gn to 0.2gn was in reference to tuning a suitable load once you find the right group node. I’m well aware that testing in 0.5gn increments is suitable for initial testing, but going finer with your increments is a good way to tune it.

And RS80 is an outstanding powder. I’ve had stunning results in my .338 Norma Magnum with the 300gn Scenar at around 93.0gn and 94.5gn. 5 shot groups...round robin style...during load testing. 

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OCW "The right way" ??  Dan Newberry I presume.

Nice shooting Catch22 but each to his own.  I get similar results shooting groups of five in one weight, then five more at another weight etc.

I don't buy the rational for round-robin shooting 'spreading the errors across all groups equally" so thereby reducing the effect.  Voodoo statistics.

Regarding charge weight increments:  0.1gr is  0.11% of the likely load of 95gr for a .338 LM.  I do not buy the idea that one could resolve the difference from all the other factors.

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9 hours ago, Popsbengo said:

OCW "The right way" ??  Dan Newberry I presume.

Nice shooting Catch22 but each to his own.  I get similar results shooting groups of five in one weight, then five more at another weight etc.

I don't buy the rational for round-robin shooting 'spreading the errors across all groups equally" so thereby reducing the effect.  Voodoo statistics.

Regarding charge weight increments:  0.1gr is  0.11% of the likely load of 95gr for a .338 LM.  I do not buy the idea that one could resolve the difference from all the other factors.

Forgive my ignorance, but what is the round-robin method as opposed to shooting groups (3 or 5) in charge weight increments?

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If you have 5 loads and you start at 90 grain, 91, 92, 93, 94, 95 Yo shoot 1shoot 90, 2nd 91, 3th 92 ets... When you get to last you wait to cool barrel down and than you go from back to 1st shoot. 95, 94,93,92,91,90 ... so you repeat again now from start of 90, 91,92....till you empty box 

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Ah, many thanks for the explanation. Now I understand why Popsbengo disagrees with it, and I agree with his logic.

I won’t hijack your post any further by elaborating on my load development methodology.

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Gents, the round robin’ is simply to remove the potential differences in barrel condition, not ‘voodoo’. 

Some barrels like a few rounds down them after thorough cleaning - I won’t even start on cleaning - easier to talk about Brexit/religion etc!

The thought behind it is the different loads will experience an even degree of barrel fouling as the testing progresses.

So removing PBG’s potential issue, as he cleans his rifles after every shoot, so after a couple of sighted/fouler his fist test group sees the barrel in condition X, his next group condition Y etc. But if you fire sequentially (round robin) then the different loads see the same degree of fouling i.e. if your barrel needs say 20 rounds to settle down then not using the round robin only your last test groups see the best barrel condition.

Personally I do not do round robin as I do not clean the snot out of my barrels every time I shoot, have yet to see why?

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Round robin also evens out variables such as wind when shooting groups. By evenly distributing shots across the group, you minimise the potential of misreading group size which may or may not have been negatively affected by wind changes.

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I think i will load group number 4, wich was 93.5 grains of RS80. This was at 300m range and i had a lot of problems with my sand bag/mirrage

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