Which way to Get back in tune?

[NC/Br Shooter]

Here's a better photo of the ladder I shot today.
29 to 30.2. 30g not pictured.
So, by the looks of things, this kinda verified what I had going. Just today, the best group was 30.2.
I had a good group at 29.8 except for the one shot ther that went some low, that piece of brass was neck turned some.
I'm about to decide to load two different batches of brass for Saturday. Load 40 pieces at 29.8 and 40 pieces at 30.2.
I know that's a .4 swing But Iv heard of people having ammo for match day with.3 grain swing.
I get as many sighters as I want. All I'm wanting to is get ten Xs. If I get more than 7 I'll call that success too. Iv only shot 6 at this particular match. The speed difference between 29.8 and 30.2 is about 40fps.

 

[JFrank]

I’m curious as to why you don’t just load at 30.0 gr ?

 

[NC/Br Shooter]

I’m curious as to why you don’t just load at 30.0 gr ?

That why I started the thread, wanted to know which way to go and why. I had two outings where 30 did not shoot one hole..
Since the thread started, Iv shot twice and 30.2 was great and 29.8 was great. In different conditions.

 

[JFrank]

Maybe I missed the part about what bullet and powder your shooting ?
I struggle with this stuff myself, I see where you are coming into tune but I’m not seeing the top end ( where you go out of tune) beyond 30.2 so all one can judge is what is posted, I don’t think you could go backwards to get in tune if 29.8 is sporadic.

 

[NC/Br Shooter]

Maybe I missed the part about what bullet and powder your shooting ?

It's a interesting thing to figure out to how the conditions changes a load. I seem to have tune between 29.8 and 30.2. with just over a hundred rounds through bbl I'm still kinda new to figureing out how a bbl changes throughout the break in process, speed, and throat erosion.
I'm shooting 6br, 68s, vv133. , in a 13.5 twist bbl,

 

[NC/Br Shooter]

Maybe I missed the part about what bullet and powder your shooting ?
I struggle with this stuff myself, I see where you are coming into tune but I’m not seeing the top end ( where you go out of tune) beyond 30.2 so all one can judge is what is posted, I don’t think you could go backwards to get in tune if 29.8 is sporadic.

Last time I shot. 30.2 was the highest I loaded for.
From previous advice, I was looking for tune below 30 because of conditions. That's kinda why I didn't load over 30 much.

In the situation at hand. I'll look up the forecast, and see which conditions will be closest to targets I have in hand. All this is to try and be in tune for Saturday. I had mentioned that I'll take two different loads for Saturday. I'm about to think I'll take three. That sounds crazy. But It would be something like 29.8, 30, and 30.2.
I already have 30 rounds of 30 ready. I got plenty of brass. I could load 30 pieces of 29.8 and 30 pieces of 30.2.
First card shoot two shots a piece on sighter target . And see.

Any suggestions on this theory?

 

[gunsandgunsmithing]

People have always looked for shortcuts or a way of putting these things into a "spreadsheet", if you will. Always being a fairly long time, I still feel like there are too many variables. Hence, a large group of top shooters load AT the the range. Tuners have the same affect as loading at the range. By one means or the other, you are affecting bullet exit time relative to a muzzle position that gives best accuracy. Most that load at the range or use a tuner, adjust based upon group SHAPE. I've been preaching this for about 10 years but it still hasn't hit home with a lot of folks. I think they look at tuners as being magical. mystical or bs. None of which is the case. The best shooters learned what to do to powder charge based on group shape and size. The same for tuner users, but their truck was squatting less on the way! Lol!

I guess it will always be the case but it seems like people are looking for an instant answer more than ever to tuning. I have the answer...There's NOT one! You have to do the leg work to know what powder charge, seating depth ot tuner settings do to group shapes. That IS the shortcut!! To me, tuners are wayy easier but I learned with tuning traditionally and then carried that over to tuners. By ANY means, if you don't know the value of any change, you're pissing up a rope and guessing. You might find a sweet spot but lost unless you know those values, in order to maintain tune all day, every day. You're the guys that will struggle with grand aggs, especially multi day ones. It only comes from testing, really. I've done a lot of that with my tuners but I can't do it all, for ever gun, every case, every tuner, every powder and every condition ywe shoot in.

The beauty is...If I can do it...and many before me...So can you! There's no magic and no secret to tuning but you have to do the work or accept your results as what you were willing to do to win. Your last group or sighter will seldom lie. The best advice I have is to learn to listen to what it TELLS you and tune based on that. I promise, I'm not making this up. What the op wants is the same thing we all wanted before tuners and after. You have to know what you're doing with both methods. There is no easy button but there are buttons that get you close .....if you're happy with 2nd place. It's only gonna get harder. So get on that 2nd place train now, before it leaves the station.

 

[JFrank]

Any suggestions on this theory?

I could be wrong and I try not to give advice but I don’t think you have laddered far enough to see the upper edge of the node you’re working.
@gunsandgunsmithing can a tuner fix that ? I really don’t know.

 

[NC/Br Shooter]

Any suggestions on this theory?

I could be wrong and I try not to give advice but I don’t think you have laddered far enough to see the upper edge of the node you’re working.
@gunsandgunsmithing can a tuner fix that ?

I believe you. I haven't. Like I say. This gun is just over 100rds. And the only thing I did see one the first ladder I did wasn't real good at 30.4.
The last one I showed, I was anticipating the tune to be at a lower charge, given advice here on what I was saying the conditions were. It will be done again after Saturday for sure, by that time. The bbl will be shot more and cleaned back up. Ready for another ladder.

So here's a question,
What would be the typical charge window for
vv 133 and 68g bullets? I know it varies, gun to gun, lot to lot, day to day. Say .3 , .4, grain window!

 

[JFrank]

IDK
If you run a charge ladder through the node you have now upwards until you find the next node (approx 30.1 +3 % =31.0 ish) or hit pressure you should find plenty of data to interpret as in how wide the node is and when it starts to shoot poorly, until then you’re just guessing.

Again I’m not giving advice Im just sharing something I’ve been guilty of myself.

 

[Clancy]

You wouldn’t be having these issues with N135. I know you’ve said you have no interest in changing, but this is just going to be the way of N133. It’ll change weekly, daily, hourly.

I have shot the exact same charge of N135 since my barrel had 35 rounds on it and never once been disappointed. My accuracy node is about .8 grains wide.

 

[NC/Br Shooter]

You wouldn’t be having these issues with N135. I know you’ve said you have no interest in changing, but this is just going to be the way of N133. It’ll change weekly, daily, hourly.

I have shot the exact same charge of N135 since my barrel had 35 rounds on it and never once been disappointed. My accuracy node is about .8 grains wide.

This is some useful information. I had bought some 8 lbs of 133 on the idea of building a ppc. Just didn't want to hunt down brass. So I figured I'd build the closet thing I could to a ppc in order to shoot the 68s.
The part you mentioned about accuracy node being .8 wide. Stuff like that helps interms of what to look for in the future.
I'll definitely keep 135 in mind.

 

[Murray Brook]

@Bra/shooter
N-135 is a great powder in the 6br with 64-68 gr bullets. In my rifle the 2 best powders with these weight bullet are AR-Comp and N-135. I was led to AR-Comp by Bradley (@urbanrifleman ) and it proved to be super in my rifle. Then when Alliant began to extort us shooters I decided to rid myself of their Powders. When my supply is exhausted then there will be no more. I began looking for a replacement and tried N-135 and it is working out just great for me. I feel you will not be disappointed by trying it. JMO

 

[holstil]

Depends on whether you're asking about humidity as in external (conditions), or as in moisture content in the powder. If your powder is changing, you will have to move the powder for tune some. But not even close to the crony difference. So in that situation, the crony will be dead ass wrong, although I've found the direction to be true, however the amount was something like a 1 to 4 ratio when I tested that.

Tom


Edit to add pictures that took a bit to find

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View attachment 1535213

So with my lot of 4895, a 17% change in powder humidity didn't kill it, but it did move it. I get roughly 10ish fps per tenth, so the crony says move it 4 tenths. The paper at 1,051 yards said to move it 1 tenth....So in this case it just tunes at a different speed.

View attachment 1535215View attachment 1535216

It wasn't the most pleasant day, but I gathered some knowledge lol.

Tom

Was this test same day same zero two different targets with powder density being the only difference? If so, curious how you were able to control/measure humidity in the powder.

Interesting how much higher the lower speed printed.

Thx for sharing

 

[jelenko]

" There's nothing to this"

This is poison!
Every time I get to thinking this, my scores tank. And it can take a fair amount of work for me to figure out what I'm doing/not doing that's causing off call shots.

 

[tom]

Was this test same day same zero two different targets with powder density being the only difference? If so, curious how you were able to control/measure humidity in the powder.

Interesting how much higher the lower speed printed.

Thx for sharing

Yes those were ran consecutively thay I shared. I did the 65 and 85 consecutive later that day, and 85 missed the paper lol. I wasn't thinking, and everything was zeroed with unmodified (dryer) powder for sighters. The poa is the white 2" sticky inside the black 4" sticky, so you can see the poi difference in the pics.

These were modified by taking 8oz of powder and locking boveda packs inside the bottle for several months. There's cheap probes out there, that can be used for just monitoring. The ones I have are pretty cheap China junk. But the cord is small enough I can slit the male threads on the bottle and get the cap over it. All in all, I would say it's pretty stable but does move a little over enough time. The larger the batch, the more stable it seems, or takes longer to start moving. So in a lot of ways, for those of us that load at the range.....it actually causes us to need to load at the range lol. Let's just say it's made me rethink the vial thing!

Tom

 

[holstil]

I don’t see much if any difference with regard to relative humidity 300 where I test but often something pees on my tune that I haven’t quite pin pointed. Perhaps I should keep a better eye on powder density.

Long time ago I gave my chrony lead poisoning for lying to me about what I should be seeing on the target. Information is key.

 

[ArtinNC]

I never keep records of different weather conditions , that I'm going to start doing . But I allways get my best groups with 31.0 grs of Varget and 65 gr Dlablos . with groups from .202 down to .051 and usely around .153 . My barrel is a twice rechambered Broughton 1:8 .272 neck , shooting .005 off rifling . And yes I know that bullet is cranking . I haven't shot this in Hot weather ether .

 

[gunsandgunsmithing]

I never keep records of different weather conditions , that I'm going to start doing . But I allways get my best groups with 31.0 grs of Varget and 65 gr Dlablos . with groups from .202 down to .051 and usely around .153 . My barrel is a twice rechambered Broughton 1:8 .272 neck , shooting .005 off rifling . And yes I know that bullet is cranking . I haven't shot this in Hot weather ether .

Those Broughtons were good barrels. They never recommended them for a 6 PPC with n133 due to the way the pressure builds with that case, that powder and light bullets. This came from Tim North, the owner for several years of Broughton. But a 6 BR and N135 or a couple of others, they would flat hammer.

Your post is to my previous point, though. Sometimes you find a load that never shoots bad, even when slightly out of tune. It may not shoot great like that, but still good. In today's game, I actually prefer a bbl that shoots big when it begins to go out of tune over one that shoots "good" even slightly out. We just can't leave a little on the table any more. One that shoots big as it progresses out of tune, "talks to me." It tells me clearly when I need to tune the load or tuner. It simply makes it easier to stay at PEAK tune rather than one that will fool you in conditions and while the clock is running. Yours may not have been one of those but most are. And since I'm kinda slow, I need one to hit me over the head and scream "tune me." I do this by group shape by far more than anything else, so when those shapes get big, I KNOW I have to fix it.

 

[ArtinNC]

This barrel started out a 6-284 that I have shot in 600 yd match and had 3 shots in a inch but never could get all 5 in there , so was probably out of tune . Then it went to a 6 BR with a long throat .125 that I was never happy with and now with a .075 throat .