What do groups look like when a barrel dies ??

B

BJS6

Guest
Will a barrel that is just starting to die exhibit any particular trend in the groups ?

I assume that the barrel will just stop shooting small groups and the groups will open up all over rather than show vertical or some other obvious trend.

Does a dying barrel usually just open up consistently or can they tease you with a couple of nice groups and then throw some high 3's ??

I am beginning to wonder about my 1000 round old Kreiger 4 groove !!

Bryce
 
Bryce

It is generally the agg that suffers, usually NOT from a bunch of big groups, but tossed shots. In other words, the thing might still shoot small groups, but it will toss enough shots to wreck the agg.
That is why I set barrels back on a regular basis. I try to head things off before they gets nasty. Skip Otto always said "nothing shoots like new brass" My addition to that would be "nothing shoots like a fresh throat".......jackie
 
Thanks Jackie.

I am getting a some vertical in recent (preloaded) practice groups. A quick test in so so conditions seems to indicate this is just load tune related but with 1000 rounds down the barrel I got to wondering.

It has been a case of fairly consistent vertical rather than tossed shots here and there so hopefully a bit of a tweak on the load is all that is involved.

To make matters more annoying I have just swapped to an Edgewood bag set when this happened. Of course swapping back to the Protektors made no difference but it all conspires to give me that "uncertain" feeling until I have seen some more decent groups on paper !!!

Hope the local guys don't read this, they might think they have one less guy to worry about at the nationals !! No such luck, I hope to have 2 new barrels ready before the shoot if they are needed !!

Bryce
 
BJS6 said:
Hope the local guys don't read this, they might think they have one less guy to worry about at the nationals !! No such luck, I hope to have 2 new barrels ready before the shoot if they are needed !!

Bryce
Click to expand...

Bryce, you'll have to admit though, you have learned about 4 years worth of learning with that barrel. Some Kriegers will go about 1800 or so unless the load is real hot.

Have you moved the seating depth to follow the throat erosion?
 
Jerry,

This barrel and the help of some good people here on brdotcom helped me to a very close (0.006) second place 2 gun in our North Island champs a few weeks ago. Not a big group of shooters down here but I was in some pretty good company in the top half dozen or so at least ! OK for my first proper match.

I do believe it has been (maybe still is) a pretty darn good barrel. I have a feeling that I may have a better first bench rest barrel than I am aware of, hope I am wrong and they all Kreigers shoot like this one !!!

Actually there has been no noteworthy erosion. The seating depth to just touching (my datum) is no more than a few thou different to what it was after the barrel had say 150 rounds down it. There is more variation in the different orders of Barts I have been using than there has been measurable erosion. About 1/3 of the rounds have been at 29.0 grains and the other 2/3 up around 30 grains.

I hope I am worrying about nothing with the barrel but I also don't want to assume it is OK and spend time, powder and bullets trying to tune a barrel that is just no longer up to the job !!

Bryce
 
Bryce

Jerry made a good point. As your throat wears, 9and, at 1000 rounds, it is worn), you have to keep moving the bullet out to maintain the correct 'jam". As you do this, you are also increasing the effective case-chamber volume.
You might have to go up on the charge a tad to get the tune back where it should be.
Just a thought.........jackie
 
Thanks guys,

Jackie, based on my just touching seating depth there doesn't appear to be very much erosion at all. However rather than just test powder I'll start by testing seating depth (making them longer) and see how that goes.


Nader, I am not rich but value my time and sanity to much to work very hard trying to make a has been barrel shoot again !! Hopefully it is just the load that is giving me some vertical but as you said, if the barrel is toast at least I have a good way to form brass for the new barrels !!

Bryce
 
BJS6 said:
Jerry,

This barrel and the help of some good people here on brdotcom helped me to a very close (0.006) second place 2 gun in our North Island champs a few weeks ago. Not a big group of shooters down here but I was in some pretty good company in the top half dozen or so at least ! OK for my first proper match.
</snip>
Bryce
Click to expand...

Congratulations Bryce!
That ROCKS!
 
My addition to that would be "nothing shoots like a fresh throat".......jackie

I agree Jackie... Totally.
 
BJS6 said:
Thanks a lot. I was pretty :) ! Just hope I can keep it up.
Click to expand...

I’m sure you will! :)
Your obviously a very driven BR shooter asking all the right questions and then putting them to use. I enjoy following and learning new things from your interesting threads, and have little doubt you’ll be a tough competitor for years to come. Good luck in future matches and keep us informed!
Jim
 
BJS6 said:
Thanks guys,

Jackie, based on my just touching seating depth there doesn't appear to be very much erosion at all. However rather than just test powder I'll start by testing seating depth (making them longer) and see how that goes.



Bryce
Click to expand...
Bryce, that "just touching" setup is tricky, tricky, tricky. Makes for a lot of 4 and 1 groups!!
 
I just use that as a datum Jerry, I am in fact jamming them 20 thou past that depth.

I see no significant measurable erosion but perhaps the wear is still effecting the actual resistance to bullet start ??? One way to find out, seat'em a bit longer and see what happens !!

Bryce




JJ-1A. Thanks, I sure hope you are right !!
 
You must log in or register to reply here.
Back
Top