Adjust seating depth or twist the tuner after buying a new lot of bullets

[Raydee]

As a barrel throat starts to erode, can a tuner adjustment be made instead of moving the bullet out.

**Edit** I originally thought that barrel throat wear was the problem with my group’s suddenly going out of tune but realized that the bullets I just opened were a different lot. I made a slight tuner adjustment which seemed to get everything back on track but it turned out to not be the case. The plan is to go back and start with a full seating depth test and tuner test with the new lot of bullets and hopefully find the same accuracy that I had with the original lot.

 

[Bill Norris]

As a barrel throat starts to erode, can a tuner adjustment be made instead of moving the bullet out.

Some would probably say yes but if it is true that seat depth and tuners control entirely different aspects as Tim Sellars explains in a podcast "Believe the Target" with Erik Cortina then it does not seem to be the case.

 

[gunsandgunsmithing]

I haven't chased the lands in a long time now. I've always been able to stay on top of it with the tuner. Since a single mark or so can make a pretty big difference though, I cringe at the word "twist" when it comes to a tuner. Rather, it should be a very methodical change of setting. Different terminology.

 

[ELR LVR]

Some would probably say yes but if it is true that seat depth and tuners control entirely different aspects as Tim Sellars explains in a podcast "Believe the Target" with Erik Cortina then it does not seem to be the case.

There is a ton of great info in that video Bill, Thanks!
One thing I picked up I never thought about was
testing 2 different velocites to exemplify what the barrel movement is doing
then
tune that out

 

[Bill Norris]

There is a ton of great info in that video Bill, Thanks!
One thing I picked up I never thought about was
testing 2 different velocites to exemplify what the barrel movement is doing
then
tune that out

Yea I have watched it several times and seem to pick up on something each time. It appears Tim has done his homework with building tuners and testing many years.

 

[ELR LVR]

As a barrel throat starts to erode, can a tuner adjustment be made instead of moving the bullet out.

I have not had to chase lands once a good seating depth is found
Since the bullets relationship is not so much "Ogive distance to the rifling"
but more the exit timing of the bullet in relation to the barrels position
I don't know why one would chase the lands to try and keep the bullet the same distance from the rifling
when the seating depth is actually more adjusting the exit timing of the bullet
OR:
Even as the throat wears, the barrel should still vibrate the same way
Edit: I may have jumped the gun here in my own experiences with the particular brand and barrel profiles I like to use, and may be different with brands that wear more quickly
I'm thinking of little throat erosion over many hundreds of rounds
as opposed to say .300" throat erosion which very well may require a seating depth change
------------------
I have however, adjusted charge weight to compensate for velocity loss over time.
this may or may not, require a new seating depth to compensate for the new charge weight
One rifle example: I have used the same seating depth for over 1200 rounds
I just took it out and shot it the other day and it was still on point at 485, 840 and 1340 yds
(This is how I proof a trajectory chart, is if all predictions are on for 3 different yardages )
------------------
be sure to change and test only one thing at a time before moving on to changing the next thing.

 

[Raydee]

I am in a pretty wide seating depth node so it is possible that the throat erosion is a non factor, it could be just a change in weather that a slight powder or hopefully a tuner adjustment can tune out.

 

[Bill Norris]

I am in a pretty wide seating depth node so it is possible that the throat erosion is a non factor, it could be just a change in weather that a slight powder or hopefully a tuner adjustment can tune out.

If it is just a slight weather change then the tuner will most likely fix it.

 

[YoteChaser]

Oh the science of our sport..... So many things can effect the outcome of what we are trying to achieve

 

[Bottom Fodder]

I’ve chase lands: there I said it so go ahead spank me

 

[JEFFPPC]

I’ve chase lands: there I said it so go ahead spank me

I don't chase the lands but also believe there is most often more than one way to skin the cat. If it works for you, all that matters.

 

[tom]

Everything I've witnessed indicates that seating is relationship based, and really close to 0% exit timing if that helps. More obvious on stuff that actually erodes, and of course helps if the rifle can shoot the difference.

Tom

 

[Bottom Fodder]

This particular barrel (6BrX) had over 3000 rounds down it when it started loosing it accuracy it started life with a hard jam and when I checked it was jumping no longer jam so I made the adjustment back to jam and added a tenth more powder and the accuracy came back. The 6 BrX is known to like pressure and jamming plus more powder will increase that in my mind. As for as exit timing or would tuner fix that problem I will let the experts decipher that. The target tells me It likes what I did

 

[marchx]

Which one of two methods: (a) tuner, (b) seating depth for tuning your rifle do you find easier, less time and material consuming and more consistent?

I am not a tuner guy, but would like to hear from people who tried both methods.

 

[SKWERLZ]

I never jam bullets so I don’t chase lands.
Some barrels I don’t need to change the seating depth it whole life.

I do have a tuner on my next 6bra barrel and am looking forward to see how that plays out.

 

[LRPV]

Everything I've witnessed indicates that seating is relationship based, and really close to 0% exit timing if that helps. More obvious on stuff that actually erodes, and of course helps if the rifle can shoot the difference.

Tom

That last sentence was a mouthful.

 

[Raydee]

Happy to say 5 graduations on my tuner made a world of difference.

 

[Bill Norris]

Happy to say 5 graduations on my tuner made a world of difference.

Very good.

 

[Bill Norris]

Which one of two methods: (a) tuner, (b) seating depth for tuning your rifle do you find easier, less time and material consuming and more consistent?

I am not a tuner guy, but would like to hear from people who tried both methods.

I do both. That way I'm sure I've done all I can to make it work. Simply made it a part of the load development.

 

[MikeRu]

I chase (the lands) and spin (the tuner)