.224 throating dilema - Advise appreciated.

[Jeff A]

I have a Savage bolt rifle (PTA action) that I built on which I installed a Shilen 1 in 8 twist barrel chambered in .223 Remington. I made a serious mistake when I ordered the barrel in that I did not state a throat depth or supply Shilen with a dummy round. After shooting this rifle I have found that it likes the Berger 73 grain (#22420) bullet as well as the Sierra 77 grain (#9377) bullet. Both are boat tail bullets and both shoot in the 3’s and 4s. The problem I am having is that when loaded, the neck of the case barely holds the bullet because the base of the bullet is so far down inside the case. This is especially true with the Berger because the section of the bullet that measures .224” extends only about .150” above the boat tail before it begins to taper. I have had bullets of loaded rounds fall inside the case. Complicating this issue is that I am using a full length bushing die which does not size to the junction of the neck and shoulder leaving a pretty small area of the neck that is sized. I have not checked the loaded rounds on my concentricity gauge as I’m sure that just checking them will cause more run out than I might already have.
I feel resigned to the fact that I am going to have to send this barrel back for re-chambering causing expense and down time. I would appreciate comments on the following:

• Should I abandon my neck sizing program on this rifle and go to full length resizing?

• If I send them a dummy round using the Berger bullet seated to a Comparator length of 2.0385” it places the beginning of the boat tail just about at the lower part of the case neck. The Sierra bullet seated to the same Comparator length as the Berger is essentially in the same place relative to the lower part of the neck of the cartridge. Do you see any problems with this?

Your thoughts would be appreciated.

 

[stool]

if you plan to shoot just those bullets...have it
"throated".
just remember as it wears you will be moving the bullet out..so pick a short start and move as you shoot.

 

[Jeff A]

if you plan to shoot just those bullets...have it
"throated".
just remember as it wears you will be moving the bullet out..so pick a short start and move as you shoot.

Thanks. I'll keep that in mind. It does bring up a question. If you send a dummy cartridge, do they throat it so there is no jump?

 

[Jeff A]

PTG makes a hand throating reamer that you can use to do it yourself. I have not personally used one, but have talked to people that own them and they are very satisfied that the hand throater does what it is supposed to do. You might give Dave Kiff at PTG a call if interested.

One thing I'm not quite clear on, you say that you have 73s and 77s set so deep in the case they the drive band is not fully in the neck and they sometimes fall out the bottom? I have a .223 Rem chamber that has zero (0.0") freebore. It loves FGMM with the 77 SMK bullet. The bullet in this factory ammo is seated approximately 12 thousandths off the lands, but is not in any danger of falling inside the case. I also have a hand load for this rifle with Berger 80.5s, that are seated fairly deep, but are still in no danger of falling inside. It's not clear to me how your chamber could be shorter than mine with zero freebore, such that it is causing you this problem. What is the COAL for your load with the 77s and how far are you jumping them? Also, what is the trim length on your brass?

The COAL on the Sierra 77 gr load is 2.243". I am jumping about .005 as close as I can tell. What is "FGMM"? Brass is 1.75".

 

[jonbearman]

Federal Gold Metal Match How do you determine where you have the .005 thou jump.How are you measuring this. Cartridge overall length in the book is 2.260.

 

[Scott Harris]

Find a local smith who has a throating reamer. It is less than 30 min of work tops and should not cost much. Easy fix so dont worry

 

[Phil3]

I am surprised at the problem stated, but after some Internet research, has happened before. Shilen will make a barrel to suit a particular dummy round. But, from what I have seen, throat lengths are not specified on Shilen barrels. If the throats are in fact "short", how does one know for sure, an off-the-shelf barrel will accommodate a particular bullet?

http://forum.accurateshooter.com/index.php?topic=3842621.0

http://www.savageshooters.com/showthread.php?15687-308-short-throat

http://forum.accurateshooter.com/index.php?topic=2693148.0

Phil