.257 cal 65 gr. BBT Group Buy at NOE

[rsterne]

For those of you who don't know, there is a Group Buy over at NOE on the following bullet....



It will be available with a Lyman HP pin in one cavity, with a weight of about 62 gr.... and is designed to stabilze in a 14" barrel, like the common TJ's 25-20 liner....

http://noebulletmolds.com/smf/index.php/topic,1632.0.html

There are now 6 people signed up, and it takes 10 for this to go into production.... If you are interested, please follow the link to add your name to the list....

Bob

[tnt76]

Bob, I really thought this one was going to take off.  An entry level into .257, 115 - 130 ftlb and it's in the zone. Common barrel etc. I think a little more time and hopefully an off the shelf .257 pcp will bring it to popularity.
My names down.

[deadguy]

I signed up too.  I thought this would be the ideal bullet for my .257 CondorSS build.  I am really surprised this has not taken off.  Maybe too many people already have the classic Lyman .257 mold already...

[rsterne]

I have asked Al if this could be made in a smaller diameter with the same tooling, no answer yet.... I'm thinking this could be the crossover drug bullet between .25 pellet barrels and .257 PB barrels.... My idea is to have it available in three diameters.... .250 cal, .253 cal, and .257 cal (all would be 0.002" over that at the drive band).... What do you think?.... I think it should work OK in a 15.5-16" twist, if you don't drive it too fast....

Bob

[tnt76]

How did you go with Al regarding the smaller diameter versions Bob?
Would you think he could put 2 cavities of the .257 and 2 of the .255 in a single 4 cavity block?  I have both, a 1:14 twist .257 barrel and the stock 1:15.5 GM barrel for my marauder that I can swap between.
I will post this question at NOE if Al has given the go ahead for the smaller dia's.

[rintafile]

Why not size down for 0.02? There is good sizing die system on NOE's store

[rsterne]

Trent, I would not suggest that approach, you would find is almost impossible to tell the difference in the two diameters, having to measure every bullet.... JMO.... It looks like we can shorten the .250 and .253 cal bullets about 0.014" at the same time, making the boattail base a few thou larger, and increasing the stability, while maintaining the same proportions, with a single set of tooling (that is the key to being able to do all three sizes).... There should be absolutely no problem with stability in the GM barrel with that change....

Teemu, If you size down 0.007", you will have to do it in a couple of steps, and it will likely drag some lead behind the bands.... In addition, the narrower, center portion of the bullet, which is relieved to clear the rifling lands, will now bear on them, greatly increasing the bore drag.... Al has agreed to look at the possibility of having this design available in three sizes, I expect an announcement soon in the Group Buy thread....

Bob

[rintafile]

Don't get it... I have .308 corsair and it shoots very well .309 diameter bullet. That RCBS mold is .314 and cast over size,thinking .315 or so, and I sized those bullets down to .309 and there is no problem with that just need to use 3-4 different sizing die. I size bullet base up like turning those bullets upside down  and there is no lead on grease grooves nor on base.... But haven't tryed on BBT bullets sizing I mean

[rsterne]

Teemu, if you look at the drawing of the .257 cal bullets, they have a mid-section diameter of 0.248", designed to just clear the rifling of a PB barrel with 0.257" grooves and 0.250" lands.... This is so that section doesn't drag on the rifling.... If you size that bullet to 0.250", the center part will still be 0.248", but the lands in a .250 cal barrel may be only 0.243".... That means the center section, which was not supposed to touch anything, would be quite deeply engaged on the rifling lands, adding to the drag.... Even a LW barrel, where the lands are supposed to be 0.248" may drag on a resized 0.257" BBT.... so better to make the mould smaller everywhere for the airgun barrels....

NOE can vary the size of their moulds, within limited tolerances, by making the tooling to cut the smallest diameter for a given design, and then "walking" the tool around in a larger circle to cut a slightly bigger diameter mould.... The plan is to make the profile of the cutter to the original 0.257" design, but make the diameters small enough to allow cutting a mould for casting 0.250" bullets.... Then it could also cut any diameter from 0.250" up to 0.257", or even a big larger....

By not having the cutting tool enter the mould block quite as far, the overall length can be shortened slightly, which because of the taper to the boattail section would result in a shorter boattail with a larger base.... Since the longer the boattail and the smaller the base, the less the stability of the bullet (requiring a faster twist), by shortening and widening the boattail (only) just a small amount, the bullet can stand a slower twist rate.... This design was intended to be 2 calibers in length, which for the 0.257" version would be 0.514" long.... If we shorten the 0.250" version by 0.014", to 0.500" (keeping L = 2D), by having the tool plunging 0.014" less into the mould block, the 0.250" and 0.253" versions will work better in the 15.5" twist GM barrel, and have more chance of working in an LW barrel (17.7" twist) as well.... plus they would be fractionally lighter (a grain), more suitable for use in the airgun barrels.... The 0.250" version, taking into account the smaller diameter and shorter boattail, would weigh 60 gr. instead of 65 gr. for the FN solid, and the 0.253" would be about 62 gr.... The HPs would all be about 3 gr. less.... If you sized the 0.257", it would still weigh 65 gr., of course....

Bob

[tnt76]

Trent, I would not suggest that approach, you would find is almost impossible to tell the difference in the two diameters, having to measure every bullet.... JMO.... It looks like we can shorten the .250 and .253 cal bullets about 0.014" at the same time, making the boattail base a few thou larger, and increasing the stability, while maintaining the same proportions, with a single set of tooling (that is the key to being able to do all three sizes).... There should be absolutely no problem with stability in the GM barrel with that change....


Bob

Thanks for clearing that up Bob. So the "waist" of the bullet would stay in proportion to the outer diameter. I wouldn't have my GM barrel's lands drag on the undersized .257/259 waist?


Oh, and only 3 more casters needed to put this round into production now.

[rintafile]

You are right Bob. I didn't check all BBT measures. Thanks.

[rsterne]

Trent.... yes, the "waist" will stay in the same proportion to the OD, to maintain clearance for the lands....

Thanks very much to Al for deciding to offer this bullet in three sizes.... The choices available will now allow it to be used in airgun barrels as well as the standard .257 cal PB size.... The profile will be identical for all three sizes, allowing one tool to be used for the machining.... so all the diameters will vary by the same amount, and for the .250 and .253 cal the bullet will be 0.014" shorter, with an overall length of 0.500".... This length reduction and slight increase of the boattail base diameter (for the 0.250" and 0.253" versions) will allow them to stabilize in a slightly slower twist.... The 0.253" should work great in the Green Mountain barrel with a 15.5" twist, as used on the Marauder.... while the 0.250" will of course be fine in the commonly available TJ's .25 ACP replacement liner, with it's 14"" twist.... The 0.250" will weigh about 60 gr. as a FN solid, and the 0.253" about 62 gr.... with the HP versions 3 gr. lighter, of course....

All three calibers are now available at the Group Buy, please specify what diameter(s) you wish to order.... http://noebulletmolds.com/smf/index.php/topic,1632.0.html

Bob

[steveoh]

I know this is an old thread...

I missed this group buy, but then again I didn't own a .257 at the time. Now I own two.

For folks who bought this mold, how has it worked out? Any reports from Texan .257 owners? I am particularly interested in how these shoot at 100 yards.

[rsterne]

I bought both the .250 and .257 moulds…. I have not tried the .257 yet.... but the .250 cal. HP, which weighs 55 gr. shoots fantastic in a 14" twist TJ's .25 ACP barrel....







Bob

[Bullfrog]

I have this mold in .250 and both my factory barreled Condor and my brother’s factory barreled Condor loves it. His Condor is one of the newer Condors with the updated valve and his gun spits them out at 120fpe. They are coyote killers for sure.

[rsterne]

Travis, are you using the FN or HP version?.... Nice to know they fit and work well in a stock Condor .25 cal barrel.... 

Bob

[enazle]

To group out of my .257 Condor I had to back it down below 900 fps. I still have a .253 51gr I would be willing to part with if anyone has use of it.