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Barrel tuning questions

4K views 20 replies 9 participants last post by  neangler 
#1 ·
I have a question or two regarding barrel tuning (in my case, a Bergara B14r with a Harrel Tuner.

#1, I live in Ohio, and with daily temps rarely getting over 40 degrees now, will the low temps effect the grouping of ammo (Lapua Center-X in the lot that excelled in even slightly warmer temps) enough to make the tuning attempt irrelevant?

#2, would it be best to use the Hopewell Tuning Method at 50 yards or 100? At 50, my B14r with this lot of C-X shoots 0.3” groups consistently already. But at 100, wouldn’t wind drift be a factor that may give inaccurate results? We rarely have still days here.

Also, any advantage in using a 3 shot group with the Hopewell technique, rather than two?

Thanks for any input in helping make the best of my tuning attempts.
 
#2 ·
Modified Hopewell

I fire three shots and rotate tuner 5 clicks . Use target with a very small center dot as a POA. Build your group around the center dot. It's not important to hit it. Your looking for a group with the least amount of vertical. One rotatation of tuner will require 15 rds. A Harrels tuner from factory has about 15 clicks below factory zero set point. Start there or factory zero. I shoot at 50 yds after sighting in the rifle. Have fun.
 
#3 ·
Living in ME I see about the same from Nov -Apr or so regarding temps. I try & still get out during the winter occasionally but generally on days where its in the 30's & 40's.
I've done a little bit of tuning in these colder temps & it can be done. Keep in mind you may need to adjust a few clicks once the temps warm up some. But you'll be close.
What I try to do is keep the lube/barrel as warm as I can while shooting. Meaning if the conditions change after a shot or two I still shoot. The bullet likely won't be where you want it to be. No problem, shoot again quickly in that new condition & make a determination. A good steady cadence is important to keep the lube/barrel warm.
I will shoot 2 shots & adjust if the spread is pretty large but once I'm close I'll start shooting three. I shoot a few more groups of three at the same setting to confirm.
I would tune the gun @50yds personally. Thats what I shoot. I do shoot @100 in the winter months basically for something different. Tried re-tuning the guns for it & haven't had great success doing it yet. Lee says its ammo & I tend to agree.
One other thing to piggy back on what rrr said regarding POA: Click your scope 5 or 10 clicks l or r to not obliterate your POA. I tend to shoot the corners of a boxed target.
Good luck with it!
Keith
 
#4 ·
I am doing the same thing - testing/adjusting a Harrell's tuner with both an "accurized" Remington 541-T and a 10/22 (match barrel). Current temps in Maryland are a.m. 30's warming to 40's/50's by mid afternoon on some days. I've found that cooling the ammo to the outside temp dramatically deteriorates groups size and even gives misfires, so I keep the guns ambient cold, but the ammo warm.

I also use multiple wind flags. Even the lightest breezes, especially if switching, will effect group size and POI, so I am testing at 50 yards (25 is too close). I think a good portion of tuning adjustment effects will be lost in the "noise" of even light wind effects at 100 yards.

I get a kick out of all the youtube videos of guys demonstrating 22LR ammo or tuner etc. precision at 100 yards with NO attention to wind.
 
#5 ·
I have a question or two regarding barrel tuning (in my case, a Bergara B14r with a Harrel Tuner.

#1, I live in Ohio, and with daily temps rarely getting over 40 degrees now, will the low temps effect the grouping of ammo (Lapua Center-X in the lot that excelled in even slightly warmer temps) enough to make the tuning attempt irrelevant?

#2, would it be best to use the Hopewell Tuning Method at 50 yards or 100? At 50, my B14r with this lot of C-X shoots 0.3" groups consistently already. But at 100, wouldn't wind drift be a factor that may give inaccurate results? We rarely have still days here.

Also, any advantage in using a 3 shot group with the Hopewell technique, rather than two?

Thanks for any input in helping make the best of my tuning attempts.
From my experience-

#1= I have always had better results in cooler/colder temperatures and my best scores have been in the months of December-February when it is in the mid/high 30's- mid/high 40's here in the high desert environment.
I also have gotten better results tuning in colder temperatures. I don't try and keep my ammo warm and just let acclimate to the ambient temperatures. I only shoot Lapua and believe their lube is better for colder temps. I would say average temperatures with the best results were in the mid-40's - low- 50's

#2= I use a modified Hopewell method and shoot 3-shots adjusting by 5-clicks at a time starting at the true zero of the tuner, which as RR stated can be below the scaled zero of the tuner shooting at 50-yds.
I found the best results at 50yds. will correlate to the same at 100yds. taken into account the increased distance will reflect the groups size. as Keith had mentioned ammo is the key on what you will see at 100yds. again best tuner setting at 50yds. will reflect the same at 100yds.

One very important thing to remember when tuning any tuner setting which puts a shot left of POA is not good and regardless of how well it shot at that time it will not holdup and that tuner setting will fall apart. where it cannot repeat the same results as before. also, it will not wait meaning you can shoot 3-shots and let the rifle sit for a few minutes and then the next 2-shots will be off center from the first 3

Lee
 
#6 ·
bag of water, since your rifle is pretty much based on a 700 action, shorter barrel my best bet is the amplitude will be diminished, so a tuner setting less than a 100 would be my best guess. start less than zero then out 5 clicks, once finding your best tune in or out a click or 2. more than likely the 1st time you think your in tune is right. doubt with the action and barrel over 100 would be in tune..marty
 
#7 ·
Thanks for what I call "A rule of thumb" ... not necessarily carved in stone but good advice, I'm sure based on experience.

Which leads me to ask, what is the likelihood that shorter barrels will benifit from added weight?
Again, I'm not expecting the final word with no exceptions but what have you seen tendency wise.
 
#9 ·
Some barrel dimensions don't seem to allow for effective tuning.

Are there any issues tuning a relatively short barrel like the Bergara's? It's 18" long and about .83ish" at the muzzle.
I found that everything depends on how the barrel will shoot without a tuner. the better it can shoot without a tuner the less weight needed for the tuner.

As Marty mentioned shorter barrel means in most cases less amplitude, so you need less weight.
I know a Vudoo shooter that has I believe it was a 20" barrel bigger than .830 and with a lite tuner, I can't remember but I believe it was in the 4.10-4.25-oz. he is getting great results with tuner setting of 35

Lee
 
#10 · (Edited)
Three+ questions for experienced barrel tuners:

1 - Does removing and reinstalling a barrel tuner affect its optimal tuning position?

2 - Does barrel clamping pressure - how tight the screws are - affect its optimal tuning position? (What is the optimal clamping pressure? Just tight enough or quite tight?)

3 - Does the use of a sleeve between the barrel and barrel tuner (to fit smaller diameter barrels) negatively affect the ability to tune?
. - (i.e. The sleeve shown was made from a bronze bushing.)



(Yes - I have read the "fabricate an indexing ring thread"!)
 
#11 ·
1- It should not. however, I do mark the position regarding the adjustment scale and always have that centered to the top of the barrel (helps to see it better). I have a tuner which is off set to the right (bored on a drill press), and it just so happens to be on my best shooting rifle. I haven't removed or adjusted this tuner in 5-years+. not sure if the offset has any effect.

2-Yes, as too tight can alter the inside dimension of the bore. I use 13-14-inch lbs. with a torque driver.

3- I have never seen anything that will point to using a shim will cause any problems. I do believe the shim needs to be made of metal and use aluminum soda can material for when a thin shim is needed and machine the thicker shims from aluminum tubing.
I have barrels which are from .960-.850 and use shims on different tuners to swap them around.

Lee
 
#17 ·
so you have to understand this about shims and varying material used in shims, a light tuner with a 24.75 reverse taper will be affected less but will be affected than a barrel of straight and larger diameter. quite possibly a shim could cause poi on a larger diameter to be downward in the tuning cycle. so an adjustment of elevation means nothing. an adjustment of windage along with elevation means a lot.I am not a favorite of shims, get the right sized tuner... marty
 
#19 ·
Marty, that is very true and given the choice it is best to use a bored to spec. tuner.

but I have not seen any change with a tuner if used with a shim, except that it does add some weight. however, there are wrong ways to apply a shim like wrapping a barrel in layers verses using the correct single thickness or using tape or material that is not made of the same material as the tuner.

I use shims so I can experiment with tuner weights, once I find the weight for that barrel, I use in most times a bored to spec. tuner or machine a shim that is press fit to the tuner. not counting the tuners on rifles, I have around $1050 worth of tuners if I was to buy them new at $150 each, buying a used tuner and using shims is the most economical way for me to experiment.

I appreciate all the help you have given me; my rifles would not be shooting as they are without it.

Happy Holidays!

Lee
 
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