Need help with a 6 PPC Bore Rider chamber!

James M.

James M.

New member
A friend of mine who doesn't post or read the forums has a 6 PPC bore rider reamer. He has chambered two barrels and can't seem to get either to shoot. He told me that he is seating the bullets long to try to get them into the bore rider section, but the barrels are showing low velocities and inconsistent accuracy. If anyone has had good luck with this type chamber, would they mind sharing some of their tuning secrets. Thanks, James Mock
 
Lou was shooting 65 grain Berger BTs with only about .065 of the bearing surface in the case neck when he shot the unlimited aggregate and single group that are both being measured for record.
 
Bart, I told Richard that very thing ...... but you know how hard-headed he can be. By the way thanks for the bullets. I am going to test the .30's tomorrow. I am not the shooter that Jackie S. is but I expect some good things from them. I know that the Ultimates are good since I got my NBRSA magazine yesterday and saw what you and Billy did at River Bend. Billy's 2-gun .19xx sounds like a good single group for me. James
 
Question, has he actually measured the bore rider diameter. Not all reamers cut what they are supposed to. That makes a big difference. I'll wager most shooters have no idea what their actual freebore diameter is nor do they know what their actual chamber neck diameter measures.
 
James,

Several people at the Shamrock were complaining about switching to the bore-rider and having trouble getting it to shoot. Often in benchrest "one size" does not fit all. Tell Richard not to screw up the Super Shoot by insisting on using that reamer. Go with what you know works and he has the rest of the year to try get going with the bore rider.

Bart
 
Bart said:
James,

Several people at the Shamrock were complaining about switching to the bore-rider and having trouble getting it to shoot. Often in benchrest "one size" does not fit all. Tell Richard not to screw up the Super Shoot by insisting on using that reamer. Go with what you know works and he has the rest of the year to try get going with the bore rider.

Bart
Click to expand...

I wonder, with the typical bore rider chamber does the shooter have any control of the "jam" or is the leade too far out for, say, a 8 ogive or so bullet?
 
Jerry, there is no way to seat the bullet into the lands. The "freebore" diameter is about the same as the bullets diameter (as seen on the drawing). James
 
James M. said:
Jerry, there is no way to seat the bullet into the lands. The "freebore" diameter is about the same as the bullets diameter (as seen on the drawing). James
Click to expand...

In what I think the rider bore is trying to accomplish "about the same" is not close enough to accomplish what we call "in-tune". There are several variables that go into "making a barrel shoot". One is backpressure which gives some credence on how a particular powder ignites e.g. the pressure curve for a given tune.

If the rider bore is even 0.0002" smaller than the actual bullet diameter you will get one effect. If the bore is even only 0.0002" larger than said bullet you will get blow-by and coppering. I think we have all seen that.

I still assert not one in fifty even know what their freebore diameter ACTUALLY is. Most folks don't know the actual diameter of the different bullets they shoot.

IMO, this "bore rider" deal, while it may solve some of the problems in hunting guns where long bullets are used but are effected by SAAMI tolerance stackup. Look at some of the SAAMI.org drawings. In most instances the MAXXIMUM chamber and the MINIMUM cartridge dimensions can be, theoretically as great as 0.012", and in actuality even more.

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I was thinking about trying the bore rider myself, but the more I thought about the more I though, WHY!!! I even sent Lou a email or two, while I was considering ordering this reamer. Lou gave me some good advise, and said in not so many words to stick with a 1045 ppc reamer, unless you just want to play around with something different. So after talking with Lou, I decided I would keep the extra 160$ in my pocket. From what I have been told, and from what I am hearing I am glad I did.
I have 3 different shooting buddies that I know of who are playing with the bore rider, and all 3 are having issues. One buddy of mine has gone through 4 different barrels, and he is just sure the barrels are the reason he cant get the rifles to tune. I didn't say anything, but in the back of my mind, I couldn't help but wonder if it wasn't the chamber? Who knows though?
I also know, that not all reamer are created equal, no matter what design they might be. bore rider or otherwise. This is one band wagon im glad I stayed off of. For now anyway.
 
The barrel I was shooting at the Cactus was a bore rider reamer and did fairly well with it. The freebore on it is very strange looking compared to what we are used to seeing. I had made a chamber gage with the reamer and I had about .010" gap between the shoulder of the case and the shoulder of the chamber gage when the gage was dropped over a seated bullet. I was using a boat tail bullet made with a Rorschach point up die. I think the bullet is about a 7 1/2 or 8 ogive. What I am jamming, I'm not sure as I'm sure the bullet is still quite aways from what you would think as an actual jam into the lands. I haven't made up my mind about the reamer yet as it takes more time and more barrels than that to determine that. The more I've messed with reamer designs though the more I think there is something to the K.I.S.S. principle in just about everything that has to do with benchrest. I think how well you do with a chamber has more to do with how well your chamber works with your sizing die than with what the freebore shape and design. I'll chamber some more barrels with it and see from there.
 
Jackie its a new reamer that's been around about a year or so. Lou Murdica did very well with it in an unlimited match in Phoenix shooting a .12 agg. Don't know whether it was 5 shot or 10 shot groups. His reamer print is in the link below. Dave Kiff ground me a reamer in about April last year with some difference from Lou's print to mine. Mine is a little longer on some of the freebore dimensions and a little shorter on some of the other freebore dimensions. My leade has a 1 degree 50' taper at the end of the freebore. But, am not sure if this has amy significance when the bullet doesn't actually get there when it seated.

Lou Murdica's Bore Rider Print

Post concerning Bore Rider reamer
 
Thanks, Mike. You never know how something is going to work until someone try's it.

Just a thought. I would think that the actual bullet diameter would be very critical. And , as Jerry said, be sure your reamer, and the way you use it, does indeed produce a .2435 freebore
 
Thanks Mike and Lou. Nothing works well till it is given a real shakeout and you two have the time, talent, and wherewithal to do it.

IMO, the bore rider design may work well but I think there needs to be greater consideration to the bore to bullet fit. Currently most folks doing chambering don't have the time or take the time, or both, to see what their finished neck and finished freebore diameters actually are.

Mike, you said you don't know what you are jamming. Could you explain?



BTW Lou, good luck to you and Angelina. She may just whip your butt.....lets hope anyway. Old age and treachery may not prevail as Gammon says.





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Looking at Lou's drawing, this bore rider is actually a stepped" freebore as opposed to a single straight diameter?

What is the purpose of the 0.233" dimension since our smallest 6mm barrels are 0.236???


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I also think barrel twist and velocity will be important components in the outcome. Walt Berger has said he feels that the sooner a bullet goes to sleep has more to do with wind effect than simply just the wind itself as a force. That is possibly why Lou and Angelina were so successful. The bullet may come out of the barrel more stable....makes sense to me! Testing outside the tunnel may give some more clues.

I noticed on one of Angelina's targets that she was shooting in a really hard blow and she kept it all together.


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Jackie especially, look at Lou's drawing. It appears to me there is a 0.2435" freebore for 0.111" then a taper from that 0.2435 to 0.2398" for the next 0.200". then a taper to 0.233" in the next approx. 0.130"?? (my eyes are so screwed up this morning I'm having problems reading Mikes copy)
 
Thanks Lou. I can see the whole idea behind this by studying that print.
The fact is, if something works, it works. And the proof of how well something works in our World is the agging capability of the combination.

I guess my only concern would be is how many rounds would be fired before that all important free bore is compromised through natural erosion. It might be a moot point, since all barrels do erode in that area. This is, however, a little more difficult to clean up with a set-back, as you are dealing with a straight diameter for at least .111 inch rather than a tapered lead.
 
Bore Rider

Lou,
I am waiting on my reamer from Kiff, but during your post you indicated that you stopped trimming to 1.500-1.502, are you now trimming to a shorter case length like 1.495?
 
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