So-Called "Bore Rider" Reamer

[rodclark]

I've heard some impressive reports on the use of a reamer which produces a slightly elongated neck-to-lands section, called a "bore rider." Anyone have personal experience or hard performance data? The claims I've heard suggest significant barrel heat reduction as well as accuracy improvement.

[HollowPoint]

If you give it a try let us know how it worked out. I've thought about reaming the throat of my 6.5x55 Swede but I may be rebarreling it later this year so I'm holding off for now.

I've never heard of a Bore-Rider-Reamer till now. It looks like you may be the guinea pig for this reamer here on the Cast Boolits forum. I hope it works out for you cause if it does the chances are that one of the reamer rental places will rent them for alot cheaper than it costs to buy one.

HollowPoint

[sharps4590]

Never heard of it either. Is it a relatively new concept? Bore rider to me has always defined a bullet where the nose of the bullet rode on top of the lands, "rode the bore", while the shank was engraved by the grooves/rifling.

[longbow]

What sharps4590 said!

Filling the throat is one thing but I have always known bore riders to be boolits who's nose was bore diameter while the driving bands are groove diameter + a thou or two. The Lyman 311299 or 314299 are good examples of this type of boolit design.

YMMV

Longbow

[John Taylor]

They do make throating reamer to lengthen the throat so the bullet can be set out more. Weatherby rifle have a deep throat to lower pressure. All chamber reamers have a pilot that follows the bore. Never heard of a bore rider reamer.

[Der Gebirgsjager]

The terminology is foreign to me also, but to some extent bore riding is that all chambering reamers do, as the reamer's pilot rides in the bore hopefully keeping everything lined up as the reamer cuts the chamber. When I've needed to extend a chamber a bit I've used a free bore reamer. Got to be very careful with them as they can eat a lot of rifling quickly.

DG

[HollowPoint]

I did a quick internet search of these reamers and it appears it has some positive attributes and some negative attributes. The negative attributes seem to be coming mainly from those shooters who shoot many rounds a year in competition. Apparently, although they get initial good results compared to the more common throat reamers, some stated that with this type of throat reamer the throats of their rifles tend to erode a bit faster.

It's kind of like the negatives reported with over-bore cartridges like the 6.5x284 Norma and others. I don't know if the average-joe hunter/shooter would experience the same type of throat erosion as the competitions shooters or not. Heck, I don't really know much about throat reamers in general. I do know that my annual round count if I were ever to own a rifle shooting the 6.5x284 Norma cartridge would most likely last me a life time cause it wouldn't get shot nearly as much as a competitive shooter shoots his or her gun.

HollowPoint

[samari46]

I would go with a shallower angle like 1minute 30 degrees.My 98 Husky in 9.3x57 has a very shallow leade from the start of the leade to actual full height lands.I slugged the barrel and figured I would need a .372 diameter bullet to fill the throat and this is not counting the normal lands and grooves. And this rifle has lands that measure .005". So plenty of barrel for the bullet to grab on to. groove diameter is .370" definitely not your standard .368" Frank

[waksupi]

I did a quick internet search of these reamers and it appears it has some positive attributes and some negative attributes. The negative attributes seem to be coming mainly from those shooters who shoot many rounds a year in competition. Apparently, although they get initial good results compared to the more common throat reamers, some stated that with this type of throat reamer the throats of their rifles tend to erode a bit faster.

It's kind of like the negatives reported with over-bore cartridges like the 6.5x284 Norma and others. I don't know if the average-joe hunter/shooter would experience the same type of throat erosion as the competitions shooters or not. Heck, I don't really know much about throat reamers in general. I do know that my annual round count if I were ever to own a rifle shooting the 6.5x284 Norma cartridge would most likely last me a life time cause it wouldn't get shot nearly as much as a competitive shooter shoots his or her gun.

HollowPoint

I'll point out throat erosion isn't necessarily bad for cast bullets.

[cwlongshot]

I have a few I would LOVE to open up a bit!!!

My 35 Whelen is but one. Lymans marvelous 358009 is a 280g “borerider” and because I powder coat... it’s difficult to chamber. Pushing it in isn’t a issue for range time my worry is hunting and having that bullet remain in the barrels and powder in my action.. Been ther don’t much like that. ;)

255599255600

[Maven]

Wouldn't a tapering [sizing] die, i.e., one which reduces the nose and perhaps 1st driving band of the cast bullet be a much less expensive proposition? As Waksupi has mentioned several times, change the least important component first. Btw, I had such a die for bore riding CB's in my K-31's and it worked perfectly.

[GregLaROCHE]

I’ve heard that some guns have really sharp right angle where the lands begin. Some people like to take off the sharp edge(angle) so the boolit has a more gradual start into the rifling. Especially, those shooting paper patched boolits.

I agree the name bore riders doesn’t seem logical.

[gnoahhh]

I have a .30 throating reamer which works superbly with long heavy bullets. It's a tapered reamer- 1 1/2 degree included angle (that's 3/4 degree per side). It has interchangeable pilots that ride the lands from .299 to .302 in .0005" increments for a custom fit in about any .30 barrel. I feel it eases a cast bullet more "gently" into the rifling. Taken a step further, I made a swage die with the same reamer that tweaks the nose of a bullet so that it nests perfectly in the throat- in effect a tapered pin in a tapered hole. A definite improvement in accuracy is noted, but I don't know if it's really worth all the hassle. Perhaps if I were engaged in top level benchrest competition it would be something I would do categorically, but for casual shooting/hunting not so much. One downside is I find myself seating bullets to be fired in those barrels out a lot farther, especially when shorter lighter bullets are employed- not a good thing if the resulting cartridges would be loaded in the magazine.

Coincidentally though accuracy seemed to be improved with jacketed bullets too, in the couple rifles I broke down and fired jacketed bullets out of, but that could be my imagination. It certainly didn't hurt.

[Hamish]

Wouldn't a tapering [sizing] die, i.e., one which reduces the nose and perhaps 1st driving band of the cast bullet be a much less expensive proposition? As Waksupi has mentioned several times, change the least important component first. Btw, I had such a die for bore riding CB's in my K-31's and it worked perfectly.

This is exactly the reason I have size dies in .308, .309, .310, .311,,,,,,, you get the idea. "Nose" sizing, sometimes even down into the driving bands, even multiple sizes, can be very useful for filling throats or, as in cw's illustration, ride the lands but still be able to extract.

[rodclark]

Thanks for all the feedback. The reports I have allege benchest users (jacketed bullets) are experiencing accuracy significant improvement. I'm not a benchrest shooter but if barrel heat transfer is reduced I'm keen to dig deeper into this.