Can we talk about "bore riders"??? [Archive]

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seagiant

02-09-2008, 04:09 PM

Hi,
I've been casting for probably 20 years and reloading even longer,but that has mostly been for my pistol shooting. Now that prices have gone through the roof I'm looking at shooting cast boolits in my rifles and would like some clarification on the ways of bore riding boolits. I have a MN 91/30 for example and the Lee 312-180 mold. The bore riding part of the boolit is to small to be snug when I check it in the muzzle but the bands are fine. I am going to cast the chamber with cerrosafe to find the exact deminsions but using this as an example it is obvious that the bullet is small in the bore riding area but good on the bands. How do you know what size the bore riding area is when you look at different molds? Sorry for the bad description but hopefully some can tell what I'm trying to ask! Thanks

wiljen

02-09-2008, 04:39 PM

There will be variation in the bore riding diameter even within production runs of the same mold. The best way is probably to ask around and find out who already has the mold in question and have them give you dimensions. I have two lyman single cavity 311290 molds of different vintages - one casts .002 larger in both nose and bands than the other. In some regards, it is luck of the draw, but at least if you get several replies here you know what the norms are and you can keep looking until you find the one you want.

I also have a few boolits that are undersized in the nose and still shoot well, I think it is more about runout, chamber dimensions, and balance than just the bore riding dimensions. Don't count a mold out until you shoot it unless the driving bands are too small.

Maven

02-09-2008, 05:11 PM

seagiant,

"How do you know what size the bore riding area is when you look at different molds?"

The answer is you often don't know the dimension (diameter) of the bore riding nose since each manufacturer uses a slightly different alloy as its standard; uses different tolerances; and may cut molds with worn cherries. On the other hand, sometimes a CB with a slightly smaller than ideal nose section can shoot well if the driving bands can be sized so that they are engraved by the rifling. E.g., I have a E.R. Shaw rebarreled 8 x 57mm Mau. that I just purchased a Lee bore rider for. In spite of the forepart being to narrow (It's a slip fit in the muzzle with no engraving by the rifling.), it will shoot into 1" (one large hole) @ 50yd. Example 2 is my 7.65 x 53 Arg. Mau. that handles Ly. #314299 very well even though the .3035" nose is unmarked by the rifling. Indeed, #314299 may be ideal for your MN 91/30 as well.

Your question addresses a pet peeve of mine, namely bore riding CB's that don't ride the bore. Sometimes you get lucky with a commercial mold, but as Wiljen indicated, sometimes not.

seagiant

02-09-2008, 06:34 PM

Hi Gentlemen,
Thanks for the information! That clears up a lot of things for me. I take it that the Lee bullet I have is more for a 30 caliber type cartridge because of the .300 bore riding area. Maven I think you're probably right on the 314299. I went to the "cast pics" and it is a good looking bullet. that extra .003 on the nose is probably what I need for the MN. Thanks again!

wiljen

02-09-2008, 06:46 PM

you might also look up beagling. It is a process by which you can temporarily increase the size of the boolit by using metal tape between the halves. I've done this on several molds for use in SMLEs. Beagling generally adds about .003 to any boolit and can add up to .006 with a double layer of tape. It may be easier to beagle up the nose and then size down the driving bands.

seagiant

02-09-2008, 07:01 PM

Hi Wiljen,
So thats what its about! I never really understood"Beagling" before. I guess if you just want to see what a fatter bullet will do it would be an option. Thanks for the help! I think I'm going to see if anyone has a 314299 they will part with. Thanks again!

tinsmith

03-23-2008, 11:03 PM

Buckshot

03-24-2008, 01:44 AM

The bore on my 1891 Argentine rifle mikes a tight .3015 - .302 . Groove diameter mikes .3105 - .311. I know that some of the Argies run larger than this. Is the Lyman 314299 the boolit for this rifle? Or, should I consider the Lyman 311299?
Lee does not make (to my knowledge) a .312 or .313 push up sizer. Will Lee custom make a sizing die?
Jeff

..............For a SMLE, M91 M-N, Jap, or Argentine my first boolit choice (if a bore rider) would be the Lyman 314299. However, your question and some of the replies are a good reason for being a disciple of Saint Guy Loverin :-). Ain't got no steenking bore rider nose. But, since we're talking bore riders, enough of that for the moment.

Due to tolerances both in creating the mould cavity (however it's being done), differences in alloys, and then differences in the firearm itself can lead to failures to fit. In my book, if the bore rider nose doesn't ride, then neither you, the rifle or the boolit will shoot well enough to be worth expending the components.

I have 2 examples of the above and what I did to aleviate the problem. First was with a rifle chambered 40-65 and it has a .400"x.408" bore/groove. I'd bouht the Lyman 400gr 40 cal Snover boolit design. Nice looking slug but the nose was dropping at .398". I couldn't get that thing to shoot at all. No real flyers as the whole group was simply big, so I guess maybe they were ALL flyers!

To remedy the situation I decided to try bumping the boolit's nose while it was in the lube-sizer die. This entailed merely exerting extra (actually quite a bit) pressure on the boolit when it reached the stop. In the process several of them became bent. I picked out the best of these modified boolits, loaded and shot them. The difference in performance was like night and day. Naturally in bumping these things, the only part that grew any was right there at the turn of the ogive.

Then checking a few before firing there was only a narrow band that was engraving the lands. Yet that was enough to cut the group size by 2 thirds if not more. I sold that mould to a guy who actually wanted such a thing. Guess he had a rifle with tight lands?

The second example was a M1909 Argentine cavalry carbine in 7.65x53. It had a .303"X.314" bore-groove. I have the Lyman 314299 but my copy drops a nose of just barely .302". While it shot better then the 40-65, the groups were still too large and there were flyers. I also bumped these and greatly improved it's shooting. While lube-sizing is part and parcel of shooting cast lead, it is not my favorite part. Add in the extra effort of bumping the noses and it becomes a PITA. Add in that uniformity suffers and you can also get bent noses and it's just not worth it.

The remedy in this case was to take the Lyman 8mm mould #323470, which makes a 165gr Loverin. I lube sized them to .323" and then ran them up through a Lee .314" push through die. It's a lot of OD reduction but with the Lee push through's they turned out well. The rifle shot these exceedingly better then anything else ever shot through it.

This kind of explains why you see all the "Fat and Fatter 30" group buy mould's being done. Sizing one down if necessary is a LOT easier then trying to increase one's OD.

......................Buckshot

Lead melter

03-24-2008, 06:41 AM

"Lee does not make (to my knowledge) a .312 or .313 push up sizer. Will Lee custom make a sizing die?"

tinsmith,
Lee Precision will be happy to make a custom sizer in just about any diameter you want. Give them a call, and I believe the cost is $25 =$4 shipping...not terrible

Bass Ackward

03-24-2008, 06:46 AM

For $20, NEI will cut you a DD band on the nose in any manufacturers mold.

This is a narrow band that allows a one time crush fit in the bore with any mix. It provides a guide until the first band hits steel and can maintain alignment. Some claim it works.

I am not advocating this, just an option to use something you already own. Buying bore rides is a hit or miss proposition.

fourarmed

03-24-2008, 01:47 PM

The older Lyman molds may run larger than the new ones. My 311291 drops around .314, where the newer one a buddy has drops about .311.

If the nose slips into the muzzle, it may still shoot well. If you can wiggle it, it probably won't.

I recently tried "Beagling" a mold using high temperature flue tape, and found that one layer of it increases the major bullet diameter about twice as much as a layer of
aluminum duct tape does. This was with the brands available locally. Others may be different.

Another thing I noticed about the flue tape: The first time I cast with it, I got a much larger percentage of rejects than normal. Wrinkled bullets and bullets with large holes in the side of the nose were common. I had cast the day before with the same mold beagled with duct tape, same alloy, same conditions, no rejects to speak of. I cast the next day with everything the same, and had no rejects to speak of. Apparently the adhesive on this brand of flue tape does some outgassing initially.

Ricochet

03-24-2008, 06:15 PM

Checking at the muzzle of a Mosin-Nagant, you need to make sure (a) that the muzzle hasn't been counterbored, and (b) that the muzzle isn't "belled" from cleaning rod wear and in need of counterboring. Either way could mislead you about the diameter across the lands.

oso

03-24-2008, 08:22 PM

I have selectively applied abrasive to the nose of a lead boolit to lap the bore riding section of a couple of molds. In one case I got the nose a bit out or round and Beagling the bottom of the mold resulted in a nice round nose.

tinsmith

03-24-2008, 10:08 PM

Thanks for the great advice! This will give me something to experiment with. I do have a 311466 Loverin designed boolet. I'll start there. If I get a winner of a boolit/load combination, I'll post it.
Thanks again
Jeff

Razor

03-25-2008, 01:14 AM

Lee does not make (to my knowledge) a .312 or .313 push up sizer. Will Lee custom make a sizing die?

Maybe not intentionally... but I got one that sizes at .313....
( I ordered the .314 push thru )
Marked as .314 but my calipers say different...:???:
Was kinda thinkin' of lapping it out to .314 ??

Razor
:castmine:

dromia

03-25-2008, 05:20 AM

Was kinda thinkin' of lapping it out to .314 ??

If its .313" and a non stock item then I'd keep a hold of it and buy a .314".

Sure as anything as soon as you open it out you'll get a rifle that will desperately need a .313" sized boolit and you'll need to get a special sizer made, such is life. :roll:

Razor

03-25-2008, 11:21 PM

If its .313" and a non stock item then I'd keep a hold of it and buy a .314".

Fine idea dromia...!!
I'll do just that.

Razor

WyrTwister

03-26-2008, 04:50 AM