False Lands measurement

[Mikelf45]

I have a question for you gunsmiths. I have a 308 chambered in a Panda action and Bartlein barrel. Smith used a FTR reamer with 170 freebore. My measurement to the lands with a hornady length gauge should be around 2.2945. My initial resistance with the gauge is at 2.1500 and with some force I can push the bullet through that first resistance to the 2.2945. The gun shoots good but I think that if this was cleaned up it would shoot even better. I’m getting scratch marks on the bullet after forcing into the lands at 2.2945. Should I be worried about this or is there something my smith can do to clean this up. Thanks

Mike

 

[Tim Singleton]

Until you do something to remove the doubt about it. It's gonna nag at you
Find someone with a bore scope and start there

 

[Mikelf45]

Until you do something to remove the doubt about it. It's gonna nag at you
Find someone with a bore scope and start there

That was my next move. I just wanted to ask others opinion before I take back to my smith. Thanks

 

[agr516]

I would be looking for a carbon ring. My 243 AI is bad about forming a ring and will even start to leave scratches on live ejected rounds.

 

[Dusty Stevens]

Look at the freebore area. Id bet its not cut perfect due to a dull reamer or something

 

[DaveTooley]

I think your freebore diameter is too tight and you have an interference fit.
This is the reason I don't like or use freebores that are .0005" over.

 

[Alex Wheeler]

One other issue is case runout. If the case is causing the bullet to bind in the freebore it will drag and scratch the bullet as well.

 

[kendog]

One other issue is case runout. If the case is causing the bullet to bind in the freebore it will drag and scratch the bullet as well.

This.
Lots of things can cause this, hard to see on the interweb! OP, what is the throat datum measurement of a new chamber supposed to be? Some reamer mfg's put the info on their print.

 

[Mikelf45]

This.
Lots of things can cause this, hard to see on the interweb! OP, what is the throat datum measurement of a new chamber supposed to be? Some reamer mfg's put the info on their print.

Thanks for the input guys. It is a PTG 2013 FTR reamer. Headed to get it bore scoped today.

 

[Mikelf45]

Looks like it was a carbon ring causing the resistance. I guess I’ll see if I can remove. Any suggestions on the best way to remove it. Looks like JB’s or Isso from what I’ve read.

Thanks to everyone for your input.

Mike

 

[agr516]

the brownells caliber specific plugs with kroil and jb's has always worked well on mine

 

[orbitup]

How many rounds down the pipe?

 

[tmwinds]

Looks like it was a carbon ring causing the resistance. I guess I’ll see if I can remove. Any suggestions on the best way to remove it. Looks like JB’s or Isso from what I’ve read.

Thanks to everyone for your input.

Mike

Get ready, this should good for about 10 pages.

 

[kendog]

Get ready, this should good for about 10 pages.

Reminds me of the "Oil Wars" on the KTM forum.

 

[DaveTooley]

Part of my normal cleaning routine is to use Flitz or Iosso bore paste in the throat area. It becomes mandatory as a barrel ages to manage heat checking. I use a snug fitting patch and work the throat then gradually lengthen my stroke until I'm 3-4 inches down the barrel.

I don't know your cleaning routine but chemicals and time are your friend. Let the barrel soak and then use a brass brush, repeat as needed.

 

[Mikelf45]

How many rounds down the pipe?

734