Is my Freebore wrong?

[Justin_B]

I ordered a pacnor 1/8 twist in .272 neck 6mmbr a few years ago. Just started measuring the lands and got some interesting nbrs compared to others on this site. My free bore was supposed to be .080 - .085.

I measured the 87gr vmax and got 2.180 to the lands from a fire formed case.

On the 105 amax, I got 2.245 to the lands.

Both of those seem way wrong compared to others' findings with the same bullets. Just wanted another sanity check before I contact pac-nor about it.

 

[expiper]

It sounds like aprox. .000 FB compared to my numbers ...I was wrong one other time....Roger

 

[Justin_B]

Hmmm.

I have no idea how I would be getting a short measurement,assuming the barrel is right).

 

[Justin_B]

Here is a pic of a 105 amax seated to 2.255. I coated the a bullet with black ink and seated it long to put ink on the lands, then set it back to length above. Notice the black ring around the bullet when seated to 2.255. I did not notice any "land" marks on the bullet, so is the ring where it's hitting the lands?

Note that hornady tool gives me 2.245 to lands.

 

[expiper]

My old tired eyes cant quite see the lil marks...but that bullt is wayyyyy down in the case neck....Seat one out aprox 2.3 inches and see if you can close the bolt on it...,no powder or primer just in case the bullet sticks..) to find out what the "jam" length really is ...we gotta stop guessin....Roger

 

[Justin_B]

I've measured just about every bullet I have. I have a shorter freebore than ordered.

I seated several bullets out long and chambered them, got similar results.

Oh well, at least she's a shooter when I give her a favorite load.

 

[rigger]

I had a similar problem with a Pac-Nor 1 in 8 twist barrel in 6mm Norma. At the time brass was scarce so I bought some Lapua 90 grain factory loads to get me started. The throat was so short I couldn't get them to chamber. I was fortunate to have a friend that had a throating reamer. I can't remember how much he lengthened the throat to get it to be usable with longer bullets. OAL length on the 105 Amax for my rifle is right at 2.32.

 

[Justin_B]

Thanks for the feedback

 

[RJinTexas]

Juston, This why when I'm going build a new rifle or add a new chamber to one of my switch barrel rifles I load up a couple of dummy round with the longest bullet I intend to shoot,,if I'm wanting to neck turn I also do that) and send them to David at PT&G and have him make me a reamer. I then take the reamer to my smith and I get exactly what I want. When it's time to rebarrel you have the reamer to cut the chamber and all your brass will still fit.

RJ