Tight freebore in Tikka factory barrel

[Tac-O]

I'd suggest caution when using the Hornady CAOL tool. I've found it highly subjective based on the user. There are other more defined ways to make that measurement.
Also, don't assume it's tight. Measure it. Get some Cerosafe and make a cast and mic it. Then you will know what it is. Mic your bullets too.

jrock is speaking volumes in few words. Lately, I have found some what we used to call "FAT" bullets in various lots of hornady bullets. My throat dia in this particular barrel was dead nuts .2435 and the bullet measured .2435. So, there is no way that that "fat" bullet would go in this particular throat, it just pushed the bullet back in the case when you tried to chamber the round.

A good micrometer that measures to the 0.0001 is a critical part of a reloaders tool box. Igauging and Shars micrometers are good mics that do not cost a fortune.

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Yes, Scheels has a sale tomorrow and I'm planning on getting the Hornady micrometer for 50% off

I've used my Hornady coal tool enough that I know exactly what the bullet's doing in the throat as I push it in there, so I'm not concerned about this part being subjective. It takes a good firm extra push to get the bullet to seat all the way. It will suddenly release and move about 0.110 further forward.

There's few possibilities that are definitely happening:

-rough freebore and burrs are hitting the bullet
- freebore diameter is actually tighter than spec
- modified case neck is way non concentric and is causing the bullet to drag on one side as I push it in.

 

[Tac-O]

Well, maybe it'll shoot, tight freebore or not.

Ran a couple patches through the bore before leaving.

Started with the cheapest ammo on the shelf to smooth that throat. Winchester power points. Not good :/ 100yds.

Then went to my 140gr match burners loads. Starline SRP virgin brass, cci450, and 40.0gr h4350. Jumping around 0.110.

Keep in mind the wind was gusting, whipping left and right. I just held center.

25 shots I think I was making a mountain of a mole hill in this case.

Avg 2530
Sd 10.6
Es 37

 

[jrock]

bore scopes can do that to you.

 

[Bob Wright]

The 140gr match burner. It's diameter measures 0.264-

With calipers or a micrometer?

 

[Tac-O]

With calipers or a micrometer?

Calipers. I'm pretty sure my calipers are pretty accurate though. I don't think the bullets are over 0.264. I have some Hornady 178eldm that are definitely fat, measuring at 0.3087ish

 

[Bob Wright]

Calipers. I'm pretty sure my calipers are pretty accurate though. I don't think the bullets are over 0.264. I have some Hornady 178eldm that are definitely fat, measuring at 0.3087ish

Calipers are not going to do it for .0001 resolution but that's all you have. I get it. Maybe a future purchase and it would be good one. They have digital mics now. Easier to read to .0001.
It looks like it's shooting pretty good so keep lapping that barrel with bullets. It may work itself out nice.

 

[tobnpr]

A good micrometer that measures to the 0.0001 is a critical part of a reloaders tool box

I'll call BS on that one...

 

[Bob Wright]

I'll call BS on that one...

For those that have a mic and know how to use them would disagree.

 

[shortgrass]

For those that have a mic and know how to use them would disagree.

Few of these "reloaders" can barely use a caliper, let alone a micrometer,,,,,,,, heaven forbid and analog micrometer! Heck, many don't .know how to properly grasp a mic to use it . And digital? Don't get me started! Been using the same Starretts I bought in '74 all this time...

 

[MagnumManiac]

Funny how using a .0001" mic can change readings just from your body heat, huh.
Interesting thinking…

Cheers.

 

[VinceMule]

It would be an interesting discussion on fat bullets vs skinny bullets, barrel inside dia, Harmonics, and throat dia.

Some gunsmiths have a set of reamer pilots for each caliber, they determine what the bore dia is with the reamer pilots that are graduated in .0001-.0002 sets, or they use Deltronic pins. It would be nice if the gunsmith were to stamp on the outside of the barrel the dia of the reamer pilot they used. There used to be a gunsmith in Tenn. that did this on every barrel, he has passed on now. Knowing the inside dia of the bore gives you a leg up on which bullets may work the best, as a best guess only.

As bullet making dies wear, bullets get fatter. Barrels will like what they like, no getting around it. Throat dia vs fat bullets is a must know situation. If the shank on a new lot# of the same bullet gets .0003 fatter than the same bullet you worked up a load with, your groups will go to pot.

As you get older, a Mechanical Digital Micrometer is much easier to read, and you are much less apt to make a mistake. Here is an example of an excellent Mechanical Digital Micrometer that some are probably not familiar with, this is not mine in the auction,to illustrate only.

Check ebay: Mitutoyo digital,vernier micrometer 0-1".0001".Machinist tool.

 

[Bob Wright]

We did "Guage Repeatability" studies with different measuring instruments and experienced inspectors and machinists.
The human factor alone adds a lot of 'off' measurements even with quality aerospace grade measuring equipment.
Mr Monkey hands on a dial caliper can really get interesting results. Mics are not "C" clamps by the way.

 

[mdmiller]

Few of these "reloaders" can barely use a caliper, let alone a micrometer,,,,,,,, heaven forbid and analog micrometer! Heck, many don't .know how to properly grasp a mic to use it . And digital? Don't get me started! Been using the same Starretts I bought in '74 all this time...

Shortgrass, purchased all my Starretts mics and everything else in Starrett out of school in 1973. They all still work!!

 

[cajun]

I like to run a cleaning rod or thin dowel down the barrel when using the hornady tool. You can push with the tool and the rod and get a good feel for where the bullet is going in the lands. Short free bore will hamper you with long bullets but they can shoot well as you see. The saami 280 AI chamber has a very short free bore but shoots well. PS if .0001 makes a difference in anything your doing reloading your doing something wrong.