Need Help Fixing a Tight Throat

[Darth_Doug]

Got a custom barrel for my encore recently form one of the more reputable makers.

I am having trouble with verticle stringing while shooting hornady bullet reloads while it shoots winchester bullet reloads beautifully. 5" versus 1" Its difficult to close the action on the hornadys and when I removed them unfired the bullets are pulled out several mm from where they were seated. I see scuffing all the way around the bullets just in front of the cartridge neck. There is no sign of the bullet contacting the rifling.

The hornadys are still straight walled coming out of the neck at .284 where the scuffing is. The winchesters start their ogive immediately out of the neck and are .277 in the same place. Seating the hornadys deeper helped but I can't seat them down to their ogive and I am still getting some stringing.

My deduction is the throat just in front of the neck is tight.

I was considering getting some of the Tubb Final Finish Throat Maintenance bullets to open it up a thou or two.

Am I on the right track? Will it work?
Looking for some advice. Thanks

 

[butchlambert]

I personally wouldn't have the abrasive bullets in any of my custom barrels. If you want to use the other bullets, have a smith run a throater reamer to the desired depth. Sometimes you cannot use several different types of bullets in a common chamber. On my 0 freebore 6PPC there are .080 difference in seating depth between the Barts 66 wedge and the Cheek 66 boat tail bullets. I use the Cheeks with my .045 reamer.
I would say pick a bullet and throat it for that bullet.
Butch

 

[Darth_Doug]

Thanks. Not sure I am up to reaming.

I contacted the barrel maker and he said it was a reloading problem on my end!

Looks like I will shoot Winchester bullets for a while.

 

[rstreich]

...Seating the hornadys deeper helped but I can't seat them down to their ogive and I am still getting some stringing....

Why can't you seat them deeper?

 

[wal]

Darth_Doug

This sounds like the reamer that was used to chamber your barrel has zero freebore, and that the reason your winchesters have nil problems is there jumping into the lands. Maybe a seperate throating reamer was meant to be used and over thought.
I would suggest taking the barrel to a gunsmith with a dummy round of the projectile you intend to use and the overall lenght you require and he will set the freebore to suit.


wal

 

[Darth_Doug]

rstreich, technically I could go deeper. It would mean the crimp groove on the Hornady's are 3/16th" below the neck. Plus use a lighter load to avoid compression. It just didn't feel right to be that far off of the groove. If I use my OAL gage and back of of the rifling 0.05" I am right in the middle of the crimp groove.

Wal, would a chamber casting give me an idea if I have Zero freebore? The problem solver in me wants to know whats wrong before I rub money on it to fix it. The barrel maker said casting would void the warranty, but based on his reply, I don't have one anyway.

 

[rstreich]

So, what cartridge is this? Even if it is a zero freebore chamber, that's not really a problem. One way or another, you're limited in your bullet selection by the length of the freebore--it'll always be a compromise.

Just ignore the cannelure and where it is. All you really care about is where the base of the bullet is in relation to the neck-shoulder junction and where the ogive of the bullet is in relation to the lands of your barrel. It's better to have the base above the neck-shoulder junction but it's not a disaster if you're below it. With your bullet choice, it sounds like you'll only care about how far you are from the lands as it doesn't seem to want to jam for you. So, seat your bullet deep enough to be some repeatable distance away from the lands and start your load workup from there.

Also, don't be afraid of compressed loads. They're just another fact of life.

robert

 

[wal]

Darth_Doug

A sulfur cast of your chamber wont help, the problem is not that the throat is tight its just to short. To solve the problem seat the intended projectile to your required length wheather it be for magazine use or preferably keep the base of the friction ring above the neck/shoulder junction. And have your gunsmith throat your chamber to suit your requirments.
This doesnt mean you are limited to only one projectile.
Sending PM
wal

 

[Darth_Doug]

I am shooting a 7mm-08 A.I. with 139gr Hornady BTSP on an Encore action. Powder load is 47 grains of H4350 in a Remington case with a 9 1/2 primer. My goal was/is a sub MOA deer rifle I could start my son out with when he is ready.

Based on the discussion so far I have taken a much closer look at my reloading practices. Here is what I have found or tried so far:

1- Using a redding s-bushing neck die I have found my neck/shoulder length to be out of spec long after 3 reloads. This is what was causing trouble closing the action. Make that one full length resizing die on order. Throat was still marking the bullets however.

2- Seated the bullets so the ogive starts immediately out of the neck. Verticle stringing was reduced to 1.75". Width is 0.75". The boat tail is in the case so deep its at or slightly passed the shoulder main case diameter junction now.

I have started fire forming a new lot of brass, double checking at every step in the case prep process.