just measured to lands with both of bullets recently received in the mail from Midsouth.

Nosler 286grn. Partition measures 3.7"

Barnes 250grn. TSX measures 3.72"

the freebore is surprising, is this common in Lothar bbls?

This is my VZ24 9,3X62

quote:

Originally posted by grizz007:
just measured to lands with both of bullets recently received in the mail from Midsouth.

Nosler 286grn. Partition measures 3.7"

Barnes 250grn. TSX measures 3.72"

the freebore is surprising, is this common in Lothar bbls?

This is my VZ24 9,3X62

It's common in most CIP std chamberings.

not quite a half inch of free bore, not certain if this question would be pertinent here or over at the reloading forum. It would cut down on pressures for sure and do well for velocities especially in a VZ24 non-carburized.

You are only talking a difference of .020 between the two. The length of the throat is fixed. You change the amount of "freebore" by seating the bullet in or out of the case.

I have LW barrel on my AR15 in 6.5 Grendel. It practically has no free bore. Of course this isn't what you'd call a standard caliber either. Tell you one thing, it's s shooting son of a bitch.

Free bore is controled by the person chambering the barrel. Was the chamber done By LW or your smith?
I have two stainless LW barrels, 1 in 270 and 1 a 708 Rem. Both of them have very little free bore.

wetspac, my humble thanks. long throated and free bore is my confusion then. this was measured with my cleaning rod and some tape, bullet to end of bbl & bolt face to end of bbl.

ol'joe, pre-chamb. LW

quote:

Originally posted by Ol` Joe:
Free bore is controled by the person chambering the barrel. Was the chamber done By LW or your smith?
I have two stainless LW barrels, 1 in 270 and 1 a 708 Rem. Both of them have very little free bore.

Throat and freebore are two slightly different things. Freebore is the distance from the ogive to the lands. That distance changes with seating depth.

quote:

Originally posted by rem721:

quote:

Originally posted by grizz007:
just measured to lands with both of bullets recently received in the mail from Midsouth.

Nosler 286grn. Partition measures 3.7"

Barnes 250grn. TSX measures 3.72"

the freebore is surprising, is this common in Lothar bbls?

This is my VZ24 9,3X62

It's common in most CIP std chamberings.

It is, but the 9.3x62 is not the worst "offender" in this respect. There are many cartridges in which a long freebore is more common than the 9.3x62.

I just measured some 9.3x62 loaded for my R93 barrel. I can't tell you offhand how far off the lands the bullets are seated, but I doubt it will be more than about .01". Measured head-to-tip (sorry, don't have my comparator handy), they measure ~ 3.380" (250 grs Nosler AB). These bulllets are seated well into the case.

As Joe mentioned above, the freebore of a chamber is determined by the reamer (assuming no special reaming of the freebore has been done). Whoever chambered Grizz' barrels had a reamer with a looong freebore built into it.

Grizz, did you specify a long freebore, or did you just ask them to chamber the barrels for you in 9.3x62 - without specifying chamber dimensions??

A couple years back, I had a Krieger barrel chambered by a nationally (US) acclaimed smith, and it came out with a ridiculously long freebore, which caused me all sorts of headaches. (Note: a long freebore per-se does not mean the barrel won't shoot well, but I had problems with mine). This in spite of the fact I had supplied dummy rounds to establish the amount of freebore needed in the chamber. In principle the freebore can't be measured on the reamer (or so I'm told), but a smith should know - at least if he has chambered with that reamer within recent history.

Since then, I have tried to specify my own reamers, but even then, another nationally acclaimed smith decided he liked the reamer (which he would take over after having done 2 chambers for me) better with a longer freebore and supplied me more of it than I had specified... This latter barrel shot well, but it was not what I had asked for. Next time, I won't share the reamer with my smith, but buy one for myself.

- mike

quote:

Grizz, did you specify a long freebore, or did you just ask them to chamber the barrels for you in 9.3x62 - without specifying chamber dimensions??

mike, SportersExpress.com, forgot the fella I talked with but I just did a simple order-23.5"bbl and the 9,3x62 long chambered, never gave any thought of free-bore until now with current measurements.

After my measurements I searched the "archives" and noted some have had up to 1/2" freebore and with great results. I hope that is the case with me.

Push come to shove I can with some reserve get a reamer in the 9,3x64 and be happy..

Just awaiting my Redding dies.

Grizz,

It is certainly possible your barrel will shoot well in spite of the long freebore. Weatherbys often manage.

If not, I'm not convinced rechambering the barrel to 9.3x64 would make much difference in terms of freebore. As far as I can see from my CIP tables, the only difference in COAL might be about 2mm (~0.079"). If the COAL you measured is compared to mine, it looks like you might have about .34" of extra freebore. It also despends on how long you can load your cartridges for the magazine of the CZ.

One guaranteed way to get rid of the freebore, is to take ~.4" off the chamber end of the barrel, and then rechamber with a 9.3x62 reamer that 1) has a more normal freebore, and 2) will clean up your current chamber. After that, the threads have to be recut (or at least extended). Not simple, but doable (I'm assuming here the barrel contour is heavy enough in the chamber end to take the setback, they *normally* are).

The good news is that you have ordered a fairly longish barrel for a 9.3x62, and that 23" barrel length would still be ample.

Doing this modification is considerably easier BEFORE you inlet your foreend to match the barrel contour. After the barrel set-back, the inletting would not fit the (now) shorter barrel. In addition, this operation is probably best done before you have the barrel exterior finished, as you risk having to re-finish otherwise.

If you have already had your barrel mounted on your receiver and bedded in the stock, then shoot the rifle and see. Otherwise, you might consider the options of having the barrel set back before or after assembling the rifle.

- mike

Last year I had the Henriksen Tool Co make me a 9.3x64 reamer made with very little throat in fact with a 300gr Swift crimped into Swifts cannelure grove the bullet jump to the lands was approx .050. I also had a 9.3 throating reamer made as well to lengthen the throat if I so desired. Both the reamer and throating reamer were made to use interchangeable pilots which was great as the first cut rifle barrel didn't shoot at all well and the second button rifle barrel shot great but both barrels had different diameter land and grove dimensions.

But no matter what powders we tried I could not get the velocity I wanted from 300gr or 320gr 9.3 bullets so we went to the 375 Ruger instead. If anybody is interested in this 9.3x64 reamer, throater, pilots and head-space gages they are for sale as a set for $150.00 used on 2 chambers and razor sharp.