Trouble determining OAL to lands in .308 Barnes TTSX

[NickEllis]

I'm trying to find the COAL to where a .308 hits the lands in my .308 Model 70. I'm loading Barnes TTSX 168gr bullets. I'm using the StoneyPoint/Hornady LockNLoad system.

When I advance the bullet until I feel just that first little bit of resistance, the OAL reads to exactly 2.800 (corresponding to the first groove on the Barnes bullet). That seems rather short to me. Indeed, if I force the bullet in further until it stops, I'm getting all the way to 2.95ish.

So that's got me wondering whether that initial resistance I'm feeling is actually the lands, or whether I'm touching something else (maybe the first groove in the bullet as it passes the cartridge mouth?). How much would one expect to be able to advance the bullet from first touch to fully forced into the lands?

Anyone experience something similar with Barnes bullets? Thanks.

 

[rcmodel]

Who knows?

Put the gage away and buy a Magic-Marker, or a cheaper candle.

Seat a bullet very long.
Then color or smoke the bullet and chamber it.

If the marker ink or candle soot shows rifling marks?
It's too long.

Seat slightly deeper, and keep coloring or smoking the bullet and trying it until the rifling stops rubbing the ink or soot off.

That's the way we did it until modern marketing told everyone they needed a $100 buck gadget to do it less precisely.

rc

 

[NickEllis]

Another question to go along with the first: Barnes doesn't list the load data (esp. COAL) for the TTSX bullets. Anyone know how they compare to the MRX, etc?

 

[WestKentucky]

What rc said or punch a primer expand the neck until a bullet barely has neck tension. Insert bullet by hand fully into chamber and poke through primer hole with a tiny Allen wrench and push the bullet forward in the case. Remove, glue/crimp into place because you now have your setup gage. Not as hard as it sounds.

 

[NickEllis]

What rc said or punch a primer expand the neck until a bullet barely has neck tension. Insert bullet by hand fully into chamber and poke through primer hole with a tiny Allen wrench and push the bullet forward in the case. Remove, glue/crimp into place because you now have your setup gage. Not as hard as it sounds.

That's exactly what the Stoney Point does. The question is whether that initial contact one feels at 2.800 is the lands, or whether to push further in. Like I said earlier, forcing all the way onto the lands results in .2.9+. Is that a typical distance to go from touching to fully into the lands?

 

[rcmodel]

BTW: I forgot to mention that 'seating to the lands' does not always result in the most accurate load.

Factory loaded Match & Varmint ammo will generally give your best hand-loads a run for the money.

And without exception, they are loaded to standard length that will work in any rifle!

Try it, you might like it!

rc

 

[gamestalker]

It shouldn't take but just a few minutes to find zero.

I start by taking a fully resized piece of brass, insert it into the chamber pressing hard with my finger, barrel pointed straight up, if it falls out by gravity alone, I know I have a free fitting piece of brass to work with. Then I seat a bullet long, barrel pointed up, chamber it slowly by hand until I feel it touching the lands. Take this slowly so you don't get it jammed into the lands. Continue seating deeper and chamber checking it until you can push it hard into the chamber, and it will fall back out by gravity alone. Or you can use the smoked bullet/sharpie method, both work well, and are a lot less expensive than a tool that accomplishes the same thing. After a few times of doing this you'll get the hand of it and be able to find zero with any new bullet in just a few minutes.

GS

 

[NickEllis]

I'm loading Barnes TTSX, so plan on loading .05 off the lands anyways. Just need to know where to start. Good helps here, thank you. I'll give the free fall method a shot.

 

[Centurian22]

This is one of the many reasons I love my lee neck sizing die. Able to resize just enough to barely hold bullet, seat long, chamber slowly, remove and measure. Repeat 2 more times for consistency and to be sure. Very quick easy and seemingly accurate. I would agree with the expand just enough to hold bullet method mentioned above as well but the sharpy candle works too. Good luck.

 

[gamestalker]

I have worked with the TTSX in several calibers/cartridges and it's an impressive performing bullet, in my experience. Since they are a solid copper, they have a significantly longer profile, so it seats deeper into the case, this makes seating up to the lands almost guaranteed, if so desired. In other words, you shouldn't have any problem maintaining plenty of bullet shank in the neck. The canelure, or canelures on these bullets, are actually there to facilitate pressure relief by giving bullet shank material a place to go as it enters the bore.

However, because they are a solid, seating up close and personal to the lands can have a significant impact on pressures, so work up, and using data specific to that bullet is quite important in my experience. All high powered rifle bullets generally exhibit noticeably higher pressure the closer the projectile gets to the lands, it's just one of the aspects of chasing the lands, and goes with the territory. And to further elaborate, Barnes coppers actually have performed best when given a little bit of running distance in the cartridges and firearms I've used them in. This isn't to say you couldn't see improved accuracy up close and personal to the lands, but it might not be necessary, and it may even have a negative impact on accuracy and obtainable velocity.

GS