Question : Changing powders when shooting. True?

[Tactical30]

I have read in a manual somewhere if you dont clean your barrel after changing loads with different powders you will have a fall off of accuracy.

Ex 1:
If im using RL-22 with a 190gr. (.300WM) bullet and then start shooting the same bullet (or different bullet) with H-1000 I will have a fall off in accuracy if I dont clean it inbetween powder changes? True?

Ex 2:
If im using Win748 with a 77gr. (.223rem AR-15) bullet and then start to shoot a 52gr. bullet with Benchrest I will have a fall off in accuracy if I dont clean inbetween powder changes? True?

I read if you DONT clean and just shoot, it will take around 5 or so shots to get back on track.

 

[gcoulsey]

Re: Question : Changing powders when shooting. True?

I've read this before too,
However, I always start with a clean barrel when doing load development anyway, so can't say how much effect it has on .308 win.

I do notice a slight difference on my 22-250 though,
Switching bullets from 52grn amax to 52grn SMK, (both with varget)
It takes 5-10 shots for the groups to settle down and tighten up after switching.. (I don't clean my 22-250 as much as I should.)

So maybe there is some truth in it?
Anyone actualy run tests on this before?

 

[Bowhntr6pt]

Re: Question : Changing powders when shooting. True?

I have reloaded for years and years and have NEVER experienced this. To be honest, first I have heard of it.

Next time I'm out testing loads, I'll alter my methods and see first hand if it's true. In fact, I can go back and validate some info and see quickly if there is any difference.

 

[gunsnjeeps]

Re: Question : Changing powders when shooting. True?

From usrifleteams.com, national match competition threads:

One thing to keep in mind is that cleaning between powder changes can mitigate compatibility problems. Maybe the AMU shooters run a patch through their bore when they change loads.

Anyway, here is the compatibility list I compiled a few years ago. It is in no way scientific and compiled nearly 100% by hearsay.


Quote

Powder Compatibilities

Short Range Long Range OK?
2015 H4350 No
4895 N540 Yes
AA2520 N540 No
AA2520 N135 No
IMR4895 Re15 Yes
IMR4895 Varget No
IMR4895 IMR4064 Yes
IMR4895 H4350 Yes
IMR4895 N540 Yes
H4895 Re15 Yes
N135 N540 OK, No
N135 N140 Yes
N135 N150 Yes
N140 N540 No
N140 H4350 No
N140 Varget No
N540 N550 Yes
N540 IMR4895 No
Re15 N540 Yes, No
Re15 N550 Yes
Re15 N140 No
Re15 Varget No
TAC N135 Yes
TAC N140 Yes
TAC Re15 Yes
TAC IMR4064 Yes
TAC Varget No
Varget N540 No, Sighters low, rest OK.
Varget H4350 Yes
Varget N140 Yes
Varget IMR4064 Yes
WC844 Varget No
WC844 Re15 No
WW748 Re15 No
IMR4064 N150 Yes

I think the link may only work for members, http://www.usrifleteams.com/forums/index.php?showtopic=14581&hl=compatibilities&st=0

 

[gunsnjeeps]

Re: Question : Changing powders when shooting. True?

For the re15 n540 combo being a yes no the poster gave this answer:
Seriously, I have it that way because some people have said the mix is OK and some have said it is not. Since this is kind of a personal judgment anyway, I put both. For instance, if the first 4 shots were a 1/2 minute off, I probably wouldn't notice. But a better shooter would. Or there could be other factors, such as one shooter using moly and the other not.

 

[MitchAlsup]

Re: Question : Changing powders when shooting. True?

I have heard that after a number of shots of one powder it can take 5-10 shots of the next powder before the barrel comes back around. Some powders will exhibit this anomoly, and some will not. Thus, it is unwise to do load development over a powder change.

 

[noahmercy]

Re: Question : Changing powders when shooting. True?

I began running a bore snake through my barrel between powder or bullet changes about five years ago when I noticed that the first few groups after making a change would invariably open up.

I have a default load for my 300 that invariably shoots into around .5 MOA. I had a bunch at the range and after shooting a new combination that I put together featuring a different powder (and which roughly matched the groups of my go-to combo), I broke out the old standbys. Groups were double what they should have been. After two five-shot strings, the groups began shrinking until they settled back into their usual dimensions by the fifth group.

I've also seen the same phenomenon with different bullets in my scoped revolvers. It seems like they need time to "settle in" with different components, although I don't know why. Of course, after cleaning many firearms require a few rounds downbarrel to begin grouping properly, so there is obviously some dynamic dealing with the affinity between gilding metals or something.

 

[SPAK]

Re: Question : Changing powders when shooting. True?

Zediker's book on handloading has a small section in it where he talks about switching between ball powders and stick powders and vice versa having an impact on accuracy.

I asked this question a while back, and from my limited loads of RL22, RL 17, Trailboss, Hornady Amax bullets, BTSP, Sierra RN, and Nosler Accubonds I haven't had any problems going back and forth between different loads. But I also don't shoot any ball powders.

I used to pull a boresnake through the bore between each different load change, be it bullet or powder, but after experimenting with the different loads and switching back and forth I have not found any significant difference in accuracy...at least at short ranges. This is with my rifle and combo of components.

I have friend up here, that has seen a big difference in his rifle if he doesn't clean between powders or even different bullets. I don't know if it's a barrel being picky or just the combination of components he is using.

 

[gcoulsey]

Re: Question : Changing powders when shooting. True?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Zediker's book on handloading has a small section in it where he talks about switching between ball powders and stick powders and vice versa having an impact on accuracy.</div></div>

Ahhhhh that's where I've read it.. Knew I'd seen it someplace!
Without finding the book to check.. Doesn't he mention about switching different bullets
too? Or maybe that was just moly/naked switching.

 

[SPAK]

Re: Question : Changing powders when shooting. True?

He does mention switching different bullets and reccommends staying with one brand or the other if you can to minimize if you don't want to deal with the changes. But he also says that's his opinion and a thought. I don't think he's actually tested it but I can't remember for sure if that's what he said in his book.

Bottom line, if you have more than one load you like to shoot you might just have to find out for yourself...if you have two different loads that have a known accuracy, shoot one and then the other, reverse it and see what your results are.

I know it's a hassle but it'd be worth my piece of mind. I have two different loads I carry in the field hunting. One for shots up close within 350 yards large game, and one for long range work. I tested switching back and forth between the two to be sure I knew what would happen so I could carry both and not have to worry about switching back and forth when hunting.