300 prc neck bushing size

[Mikemo]

Can someone who is shooting the 300 PRC provide some input on the neck bushing size please. I am trying to get it right on the first try. I know, I know, but trying anyway. I mainly shoot steel and prefer minimal tension. I am using Hornady brass (is there any other kind)? My calculations for .0015 & 002 tension indicate a (redding) bushing of
.336 diameter. If I error, I would prefer it to be too loose. What are you all using for bushings/neck tension? Thanks!

 

[Supersubes]

The 300 PRC has a tapered neck thickness, so plan on either using an expenader ball in your sizer, or a mandrel. If you were to just using a bushing, you’ll end up with a funnel shaped neck. A .336 would get you zero neck tension at the mouth, and about .001 at the neck/shoulder junction. I personally don’t like that at all. Neck thickness variations alone will cause wildly different neck tension, which you’ll fee during seating.

I use .333-.334 bushings, and the expander ball in a hornady match die (best designed rod and expander assembly imo). A mandrel would work just as well.

 

[Mikemo]

The 300 PRC has a tapered neck thickness, so plan on either using an expenader ball in your sizer, or a mandrel. If you were to just using a bushing, you’ll end up with a funnel shaped neck. A .336 would get you zero neck tension at the mouth, and about .001 at the neck/shoulder junction. I personally don’t like that at all. Neck thickness variations alone will cause wildly different neck tension, which you’ll fee during seating.

I use .333-.334 bushings, and the expander ball in a hornady match die (best designed rod and expander assembly imo). A mandrel would work just as well.

Great info. Thank you. I was not aware of the tapered neck. I have a mandrel die, so I am thinking a .333 bushing with a mandrel. I am still short a bushing die so I'll look into the hornady.

 

[Supersubes]

The ball in the hornady is exactly .002 under bullet diameter. After you pull it through the neck, you should end up with just under .002 tension due to neck spring-back. The ball also has a very narrow bearing surface, and floats on its rod, so it will not pull your necks off center. You may not need the mandrel at all. Less that $50 anywhere. This is for the Match die, not the custom grade(same ball but fixed rod).

 

[Mikemo]

The ball in the hornady is exactly .002 under bullet diameter. After you pull it through the neck, you should end up with just under .002 tension due to neck spring-back. The ball also has a very narrow bearing surface, and floats on its rod, so it will not pull your necks off center. You may not need the mandrel at all. Less that $50 anywhere. This is for the Match die, not the custom grade(same ball but fixed rod).

That sounds like just what I am looking for. The Hornady match die may even be easier to find. Thanks for your help I am going to see If I can find one.

 

[Mikemo]

Great info. Thank you. I was not aware of the tapered neck. I have a mandrel die, so I am thinking a .333 bushing with a mandrel. I am still short a bushing die so I'll look into the hornady.

One more thing if you don't mind. I see a couple of reviews on the Hornady match and they mention using Redding bushings. Do you know if this is legit? Thanks

 

[Supersubes]

Yes, the hornady die uses the same bushings. I own lots of neck bushings, and personally prefer Wilson bushings. Over the years they’ve been better quality. True to size and nicer chamfers

 

[Mikemo]

Yes, the hornady die uses the same bushings. I own lots of neck bushings, and personally prefer Wilson bushings. Over the years they’ve been better quality. True to size and nicer chamfers

Great. It's all on the way. Thanks for your help.

 

[rknuesel]

The 300 PRC has a tapered neck thickness, so plan on either using an expenader ball in your sizer, or a mandrel. If you were to just using a bushing, you’ll end up with a funnel shaped neck.

Where can this info be found? everything I have seen on case dim. has no mention of a tapered neck. I just received an order of Hornady brass and I get the same wall thickness from shoulder to end. I want to make sure I don't mess up new ( Hard to find ) brass.

 

[Supersubes]

Where can this info be found? everything I have seen on case dim. has no mention of a tapered neck. I just received an order of Hornady brass and I get the same wall thickness from shoulder to end. I want to make sure I don't mess up new ( Hard to find ) brass.

Which brass do you have? All the Hornady I’ve measured is tapered. Hornady 6.5 PRC is this way too.

ADG could have omitted that, which would be a good thing imo.

 

[rknuesel]

It is Hornady, how are you measuring. I am using an inside bore gauge. I have found inconsistent readings when using a vainer caliper due to the thickness of the tool its self and not holding a center reading when pushed all the way to the rear.

 

[Supersubes]

It is Hornady, how are you measuring. I am using an inside bore gauge. I have found inconsistent readings when using a vainer caliper due to the thickness of the tool its self and not holding a center reading when pushed all the way to the rear.

Two methods. Ball mic on both sized and virgin cases, and blade mic on loaded rounds.

 

[rknuesel]

Hornady finally got back with me about the brass, the following is part of the email response I received from Hornady:

Recently you requested assistance from our customer support center. The following is a summary of your request and our response.

Hornady Support commented at: 04-21-2020 04:17

Mr. Knuesel,
Sorry for the delayed response. These were not made with a tapered neck thickness from when we developed it for either the 6.5 or 300 PRC cartridges. We hope this does clarify some.
Thank you