Bore rider throats???

[ingotoutdoors]

Are any of you guys using a bore rider throat? Seams like an accuracy minded version of the weatherby free bore? After countless hours of searching and reading here is what I have come up with:
7mm RUM set up for 195 Berger EOL's using a bore rider throat with the first step @.220, the second at .750 with a 1 1/2 degree lead angle. With the reduced pressure of the longer throat higher speeds should be attainable? And according to Kiff he has some shoots in the winning circle using them?
I have had custom reamers made with bullet specific throats and neck dia. in the past but have no real world experience with bore rider throats, so please school me.
Thanks, ingotoutdoors

So I asked this question in the lrh section and received zero feed back?

 

[J E Custom]

Are any of you guys using a bore rider throat? Seams like an accuracy minded version of the weatherby free bore? After countless hours of searching and reading here is what I have come up with:
7mm RUM set up for 195 Berger EOL's using a bore rider throat with the first step @.220, the second at .750 with a<script id="gpt-impl-0.7289606149580735" src="https://securepubads.g.doubleclick.net/gpt/pubads_impl_107.js"></script> 1 1/2 degree lead angle. With the reduced pressure of the longer throat higher speeds should be attainable? And according to Kiff he has some shoots in the winning circle using them?
I have had custom reamers made with bullet specific throats and neck dia. in the past but have no real world experience with bore rider throats, so please school me.
Thanks, ingotoutdoors

So I asked this question in the lrh section and received zero feed back?

Probably the reason you haven't had any feed back is because this is an experimental process
and it can cause as many problems as improvements.

What Little I know about it is that it's supposed to replace extended freebore with partial rifling.
Free bore is not an issue if properly sized ammo is used in a true concentric chamber, Plus it helps control Pressure. this system of minimal rifling for part of the free bore Is like having very slight lead angles (Less than 1o) that will cause poor initial engraving on the bullet on high velocity bullets because of starting torque.

On less powerful lighter cartridge/bullet combinations like bench rest use, it may work ok, but lead angle is very important to get good engraving on the high velocity, heavy bullets that we use.

J E CUSTOM

 

[TonyQ]

I use a PT&G 300 weatherby borerider reamer. I am shooting 230gr Berger hybrid at 3032 fps 30" hart and hbn coated bullet and bore using 86gr of n570. I am not sure how much fps the borerider adds but I am happy the way everything shoots. Here is a thread I started on seating depth test I did. http://www.longrangehunting.com/forums/f28/300-weatherby-bullet-seating-depth-test-167502/

 

[J E Custom]

I use a PT&G 300 weatherby borerider reamer. I am shooting 230gr Berger hybrid at 3032 fps 30" hart and hbn coated bullet and bore using 86gr of n570. I am not sure how much fps the borerider adds but I am happy the way everything shoots. Here is a thread I started on seating depth test I did. http://www.longrangehunting.com/forums/f28/300-weatherby-bullet-seating-depth-test-167502/

Sounds about right for a 230 grain bullet.

My load for a 225 grain is 3008 ft/sec out of a 26" barrel in a standard Weatherby chamber.

What Is your total free bore with the bore rider part and the normal free bore part ?

J E CUSTOM

 

[TonyQ]

I didn't like having a ton of freebore that's why I went with the borerider reamer. Here is the reamer print.

 

[adam32]

Basically the same as the +P stuff, right?

 

[Deleted member 46119]

I don't remember reading about this anywhere.

Can I get more of a definition of "Bore Rider Throat"?

 

[Edd]

Is this an attempt by PTG to Pirate Shawn Carlock's idea?

 

[bigngreen]

There are a number of what is being called bore rider throats, some have a more complex geometry with differing angles and some are just cutting two hight lands for a distance but the same lead angles. They've been in use best I can tell since the 80's. It's an interesting thing, I've seen a number of what would be a moderate chambering toast the throat out in very low round counts. Bench guys have been playing with it of and on, it does change the pressure curve but most I know really don't end up running much faster just with better brass life but shorter accuracy life than a conventional throat.
I've used them in very limited situations, one would be a round that is not going to be hard on throats but it needs a little pressure taken of the front end to run, situations that just let it run a little easier at the same performance.
There is no way I'd use any throating strategy other than normal for something that is a throat burner anyway, the throat will wear more even for more rounds with a conventional throat.

 

[bigngreen]

Is this an attempt by PTG to Pirate Shawn Carlock's idea?

The PTG one is different and it has to be ground into the reamer, JGS has cut dual land throat what some call bore rider since the 80's and it sounded like it was popular a little with 50cal shooters, you can just use a throater to cut the dual land throat

 

[Deleted member 46119]

There are a number of what is being called bore rider throats, some have a more complex geometry with differing angles and some are just cutting two hight lands for a distance but the same lead angles. They've been in use best I can tell since the 80's. It's an interesting thing, I've seen a number of what would be a moderate chambering toast the throat out in very low round counts. Bench guys have been playing with it of and on, it does change the pressure curve but most I know really don't end up running much faster just with better brass life but shorter accuracy life than a conventional throat.
I've used them in very limited situations, one would be a round that is not going to be hard on throats but it needs a little pressure taken of the front end to run, situations that just let it run a little easier at the same performance.
There is no way I'd use any throating strategy other than normal for something that is a throat burner anyway, the throat will wear more even for more rounds with a conventional throat.

See if I can say this another way: because of the fact that land material is proud of the groove diameter closer to the case mouth, this land material is closer to the powder "flame" and is ablated quickly causing a deterioration in accuracy.

Have I got that correct?

 

[bigngreen]

Think of it as a normal throat then cut a length of the lands away then bring it to full diameter is a given distance, there is some geometry veriations in how this is done but the effect is basically the same. So you end up with half the normal land hight, less steel less life faster progression of the throat. At least that is how some have played out, that's why I'd use it judisiously. There is a custom rifle builder that makes his own barrels and he does essentially the same thing but he does it during the reaming of the barrel then you cut the chamber and you have that second step already established.

 

[J E Custom]

There are a number of what is being called bore rider throats, some have a more complex geometry with differing angles and some are just cutting two hight lands for a distance but the same lead angles. They've been in use best I can tell since the 80's. It's an interesting thing, I've seen a number of what would be a moderate chambering toast the throat out in very low round counts. Bench guys have been playing with it of and on, it does change the pressure curve but most I know really don't end up running much faster just with better brass life but shorter accuracy life than a conventional throat.
I've used them in very limited situations, one would be a round that is not going to be hard on throats but it needs a little pressure taken of the front end to run, situations that just let it run a little easier at the same performance.
There is no way I'd use any throating strategy other than normal for something that is a throat burner anyway, the throat will wear more even for more rounds with a conventional throat.

Thanks !

Its nice to hear it from someone that I trust instead of theory and hearsay. The only dealings I have had with it was the bullet engraving issue and we solved that by running a standard reamer in the chamber.

We stilled ended up with a long freebore, but the rifle started shooting 1/4 MOA immediately. The rifle was never shot enough to see the early throat erosion potential. We also saw no difference in velocity but that was to be expected with the amount of freebore we had.

I hope the poster does not have any of these problems and gets the performance he wanted.

Very interesting post.

J E CUSTOM

 

[TonyQ]

I am out of town but when I get back I will check and see if there is any throat erosion. I have around 350 rounds though it but I have been using N570 which I also heard it was hard on throats. The barrel has been HBN coated and bullets also been coated.