Go nogo gage tolerance.

4

45C

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Is there a set amount of tolerance ( distance) between the two gages? Do it vary by caliber?

My barrel was set up using gages and I was wondering if I coul screw it in a bit tighter ?
 
6.5 PRC
My max mag lenght is is 2.980
If I load to max mag lenght closest I can get is 30 thou off the lands.

So , if I screw the barrel in will it allow me to get closer to the lands?
Is there enough tolerances to do that?

I only use reloaded ammo
Lapua brass
130 g Hornady CX
 
Difference between GO and NO GO is only a few thou. If you want to get rid of that 30 thou jump, the barrel will need to be refitted, and the chamber recut, using a reamer that isn't going to deepen the leade.
 
That’s the info I need.
I’m not going to recut.

I could look into bullets that like a bit of jump, maybe?
 
If you want to see accuracy differences seat the bullets out and load single shot, don't use the magazine. You may find little difference...
 
guntech said:
If you want to see accuracy differences seat the bullets out and load single shot, don't use the magazine. You may find little difference...
Click to expand...
Hey , that’s didn’t cross my mind.. I’ll definitely try that, good to know.
 
What rifle are you loading for?

I actually found with allot of the monolithic bullets I’ve loaded over the years they seem to like a good amount of jump. An I know in my research for Barnes info for multiple rifles allot of guys talk about it not being uncommon to jump them. I’d be curious of the CX is the same. I have some loaded but not tested just yet. Hopefully in the coming months.

B
 
45C said:
It’s a Tikka hybrid, proof barrel set up in a SA chassis.
( it’s what I want)
Click to expand...

Sounds like a nice setup! That’s the annoying parts about some mags you just can’t go longer.

I’d definitely try some loads at mag max then maybe some single feeds. I’ve heard about guys getting the best groups at 50 thou off so you never know with monos.

Hopefully something loads well for you.

B
 
FWIW my 2 Tikka T3x rifles in 6.5x55 and 30-06 both have long throats. On the 6.5x55 I load the bullets out a considerable amount and there is still a long jump to the lands. The rifles don't seem to care. Accuracy is excellent.
 
Paul_T said:
FWIW my 2 Tikka T3x rifles in 6.5x55 and 30-06 both have long throats. On the 6.5x55 I load the bullets out a considerable amount and there is still a long jump to the lands. The rifles don't seem to care. Accuracy is excellent.
Click to expand...

The accuracy on Tikkas with the long freebore is excellent because the throats are TIGHT.

A chamber cast on my Tikka T3 (6.5x55) throat, measured at .2655 diameter. The throats on most firearms are much larger and the more freebore length, the more room for the bullet to slop around before entering the leade.
 
45C said:
6.5 PRC
My max mag lenght is is 2.980
If I load to max mag lenght closest I can get is 30 thou off the lands.

So , if I screw the barrel in will it allow me to get closer to the lands?
Is there enough tolerances to do that?

I only use reloaded ammo
Lapua brass
130 g Hornady CX
Click to expand...

If you know that you are at .030" with those bullets - some Barnes bullets want .060" or more jump - is not necessarily the same from one brand to another - "jump" that you are concerned about is likely when the ogive of the bullet engages the beginning of the rifling - the "leade" - which may or may not have much to do with where the bullet tip is - which is what your over-all length in a magazine is about. The cartridge over-all length may or may not relate to the bullet jump that you experience - especially if you change from one brand of bullet to another brand.
 
Potashminer said:
If you know that you are at .030" with those bullets - some Barnes bullets want .060" or more jump - is not necessarily the same from one brand to another - "jump" that you are concerned about is likely when the ogive of the bullet engages the beginning of the rifling - the "leade" - which may or may not have much to do with where the bullet tip is - which is what your over-all length in a magazine is about. The cartridge over-all length may or may not relate to the bullet jump that you experience - especially if you change from one brand of bullet to another brand.
Click to expand...

Yes sir, I determined my measurements with Hornady compariter set, then used overall length of mag and bullet to get where I’m at now.
It’s the only bullet I have at the moment but plan on trying Barnes TTX next
 
So I just checked some numbers on my 6.5 PRC Tikka Barrel.

If I was to use the same mag length as you the jump would be the following to the rifling. (Measured in the same manner with a comparator set and OAL done at the same time.)

For the following projectiles to fit within the mag they would have a distance to the lands as such.

Nosler ABLR 150gr 0.094”
Hornady ELD-M 147gr 0.053”
Hornady CX 120gr 0.039”
Nosler E-Tip 120gr 0.006”
Barnes LRX 127gr 0.0065” (while I have great calipers the accuracy of the last decimal place is questionable.)

Hopefully that helps. As I’m not restricted by mag length in my rifle setups I cannot say how they shoot at that length.

B
 
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