Author Topic: .25 cal 51 gr. NOE Bob's Boattails (Read 43050 times))

rintafile · « **Reply #220 on:** January 24, 2017, 02:00:20 PM »

We did one test last summer with TPL. We both own Corsair .308 and that was test gun. Both shot own guns. I shoot perfectly casted and weighted bullets and TPL shoot same bullets but not weighted and so horrible looking. Wrinkles allover and holes,grease gooves was malformed... But there was no significant difference those 10 shot groups which we shot. Distance was 100M.So I don't anymore check bullets before silhouette competitions etc. Bench rest is different thing..

http://www.sihry.fi/keskustelu/viewtopic.php?f=24&t=364&start=1270

Scroll down 9th post on top of page. There is pictures of bullets and those groups. Click pictures for bigger.. I lost one and win one 10 shot groups... We didn't shoot those groups like competition just for testing purpose,so we shot quite fast and that was results

K.O. · « **Reply #221 on:** January 24, 2017, 02:59:49 PM »

just my opinion... I feel if you are getting a nice sharp base on your rounds it is better than tumbling them and getting rounded corners... no proof just a gut level feeling...

Harry Pope in the old Days made a fixture to muzzle load his rounds... why..? to keep the base of the round as clean as possible... I drink that cool-aid and believe that it is among the most important aspects of the round...

this round is very similar to the .22lr in fpe and exterior ballistics... here is a vid of some deliberately badly out of balance and aerodynamically unsound .22 lr rounds at 50 yards...

rintafile · « **Reply #222 on:** January 24, 2017, 03:05:43 PM »

Sure this test was just prove that some guns aren't so picky when it comes bullets. Of course when I cast bullets I throw wrinkeled and malformed back in pan

rsterne · « **Reply #223 on:** January 24, 2017, 11:27:40 PM »

Many cast bullets are NOT perfect at the corners of the base, because of the pressure of cutting the sprue.... This is worse with small calibers and large holes in the sprue plate.... with the base ending up rounded on one side, and super sharp on the other.... I agree that is once of the problems that destroys accuracy, and the bullets I tumbled were to even out the base.... One of the reasons I used a rebated boattail in my BBTs is to move the release point where the bullet leaves the barrel crown forward to the driving band.... and away from any base distortion due to casting and uneven sprue cutoff.... That's the theory, anyway, and the reasoning behind it....

Bob

int3man · « **Reply #224 on:** March 04, 2017, 09:29:10 PM »

Does anyone know where a person could buy some of these Bullets? I have a .257 that I want to sell, and Bob recommends that I try these 65 grain Bullets. Just looking for 50 to get started, or finished.

Thanks!

454 Big Block Chevy · « **Reply #225 on:** March 04, 2017, 11:45:54 PM »

If i could find a type of slug like this, that would work in a .25 cal Condor barrel at .250 or so, i would buy the lee melting pot, and all the lead, to cast my own.... but i'm affraid to get into this....

JumboPellet · « **Reply #226 on:** March 05, 2017, 10:23:06 AM »

454,

Is your barrel choked? Have you slugged it to see what the exact bore diameter is? I would be willing to part ways with a few if you agree to post the results (you're not far from me as far as the USPS flies).

Regards

Jeremy1982 · « **Reply #227 on:** March 05, 2017, 03:17:28 PM »

you may have better luck but my LW 25 barrel did not like them.close range I got so so results...after 50 yards it looked like bird shot.I begal my mold to get a 257 dia and my T J barrel loves them.

JumboPellet · « **Reply #228 on:** March 05, 2017, 05:24:52 PM »

I'm in the process of fitting a TJ .25 ACP Barrel to a Hatsan Gladius, I hope my results are good as well. I have tried shooting them out of a BT65 with a stock barrel and the results were terrible. But, from prior posts in this thread, that's to be expected from a choked barrel.

If anyone has a TJ .25 ACP fitted and hasn't tried these, let me know. I can spot you some test BBTs (51gr FN, 47gr HP, and 41gr FN). I only ask that you post the results, hopefully will provide some motivation for me to finish this project and get to putting them downrange.

calinb · « **Reply #229 on:** August 18, 2017, 02:30:56 PM »

I've cast almost 500 bullets from my new 253-51-HP 2-cav and fired them through my TalonP. I think I got the last 253-51 off the NOE store shelves! Pure lead FNs drop at 52.0 gr. exactly and the HPs drop at 49.1 gr. (with the pin adjusted as close to the print spec as I could get it). It's a fabulous mold. Nearly all bullets fall into adjacent 0.1 gr. sorting piles when weighed. I typically remelt only two or three bullets that don't meet +/- 0.1 gr. per casting session. That's better than +/- 0.2%, which is incredible consistency for a cast bullet!

After extensive testing in my TalonP at 50 yards, I could only achieve so-so accuracy, but so-so is all my TalonP can achieve with most pellets too.

The BBTs do their best from my short barrel / relatively low power TalonP at just under (FNs) to just over (HPs) 700 fps. My 5-shot groups are typically around 1-1/2 inches, which is about the same as I get with Kodiaks, Baracudas, and Benji Domes. JSB Kings, King Heavies, and King MKIIs group better at close to an inch. Predators are the very best in my TalonP, grouping under an inch and occasionally approaching 1/2 inch for 5 shots. (I prefer to shoot 10 shot groups, but not with the low capacity TalonP reservoir where accuracy can often drop a little after 5 shots.) I've tested over a dozen other pellets, and they are all less accurate than the pellets above, except my beagled-up RCBS 25 ACP slugs are also about the same accuracy as the BBTs.

After slugging my TalonP bore several times, I suspect my AirForce L-W barrel is limiting my accuracy, because the choke is very aggressive (tight). I’m beginning to wonder whether it has too much choke for optimally launching pellets too. I found that the barrel ID constricts .002″ in diameter in the last 1″ of the barrel. That seems like a awful lot of choke! (.0005 to .001 is typical, I think.) In slugging it, my TalonP barrel groove / land diameters go from .2546 / .248 down to .2525 / .246 at the choke. I measured the twist at 1:17.2, as others have reported here.

I asked Tom Gaylord about the .002" choke and he has never heard of that much choke. He said Harry Pope liked to choke a barrel a half-thousandth and one thousandth is about the most there should be.

Making the already short 12" TalonP barrel even shorter is problematic, because there is very little length extending beyond the front barrel bushing. However, I found that my choke is only .002 for the last 1/2 inch. The first part of the choke appears to have only .001" of constriction. After trying to slug short sections of barrel, I think I've determined that I can part-off the tightest section at the front of the barrel bushing (making the barrel about .56" shorter) and end up with a more reasonable .001 choke. I think it's worth a try anyway.

Given that Harry Pope's barrel were renowned for exceptional accuracy with slugs, I don't think chokes, in general, are the problem with airgun barrels. Rather, OVER-choking the barrel may be the problem!

I have a 28" TJ's 257 barrel in hand, but I need to retrieve my lathe and mill from 8 hours away before I can fit it up--hopefully before winter arrives. Reportedly the 253-51 shoots very well from that barrel and my slugs are dropping at more than 1-1/2 over the print size. Pushing a slug though my TJ's barrel shows both bands bottoming in the grooves at .257, so I'm hopeful they will work. Of course the 257-65 BBT might be better still in the TJ's barrel!

calinb · « **Reply #230 on:** August 18, 2017, 07:44:30 PM »

Update: Thanks to Google, I found this German L-W page, which I've never seen before.

http://www.lothar-walther.com/163.php

Technical specifications:
For the highest accuracy possible, the barrel blanks come with choke, that means a narrowing of the land-groove-diameter up to 0,05 mm at the muzzle.

So my .002" choke is probably intentional and to spec (0.05mm). The German website published land and groove dimensions that match what I measured too (within my precision in measuring a slug of soft lead).

I don't think it's possible to optimally size a bullet to fit rifling that varies this much. Believe me, I've tried! I have all the NOE sizing bushings from .252 to .258 and I even used the body bushings to size the nose different from the driving band too. Driving bands of .254 or .255 and nose sizes of .252 or .253 seemed to be the best, but it doesn't make a huge difference in accuracy, which I take as evidence that no sizing combination works well with the .002" choke!

K.O. · « **Reply #231 on:** August 18, 2017, 07:51:12 PM »

There is one more thing you can try... Knurling from undersize for the non choked bore/groove back to non choke ~bore/ groove size

https://www.gatewaytoairguns.org/GTA/index.php?topic=119504.0

Ribbonstone · « **Reply #232 on:** August 18, 2017, 08:00:14 PM »

Here is my "junk".

Am preverse about this...but If I'm going to buy projectiles, I'll buy pellets....if I'm going to shoot slugs, I'll cast them.

Only one ammo can of molds survived a major flood (like 12 feet of really fast moving salty water/cars/house parts. etc) 14 years ago. It got wedged under the neighbors front steps, and survived (kind of )

It happened to be my stash of "obsolete" molds....obsolete by both age and use). The mondern stuff didn't make it, being bashed-n-scattered over a long long distance.

Yeah...lemon...lemon aid...

The ammo can did leak a bit...which rusted up the outside a bit and cracked some wood handlles, but the cavities/mating faces were well greased and they survived fine (although ugly on the outside).

Saved an old Lyman electric pot too...but had to wire it all the way "on" and hook it to a "dimmer" to get it to vary temp (nd a pair of very old, EPA poison, asbestoses gloves).

From an antique Winchester" mold, an early Hoch molds, some pretty newish T'C type molds, and some old Lyman's. BTW: that little "collor button" Lyman single cavity mold makes an excellet .45 airgun slug...and that way-old 115gr FN Winchester mold works well (once sized) for 30" / .31"s.

So fellow survivors (after all, if you are reading this, you likely survived at least one "something" that should have killed you by now), what I did was adapt my shooting to fit the ammo supply.

So...I do occasionaly clean out the pellet trips, melt the lead down (even though it's pretty soft and not all that easy to cast) and do my own "recycle". May not be airguns shooting the recycled lead all the time, but at least I deposit it off my personal property.

NOe I have a job to do...scrub 'em up (lucky the mold cavities have still survived the long storage) and grease them up once again...it's Hurricane season, and I'd like to give the suvivors a fighting chance.

calinb · « **Reply #233 on:** August 18, 2017, 08:01:08 PM »

Quote from: K.O. on August 18, 2017, 07:51:12 PM

There is one more thing you can try... Knurling from undersize for the non choked bore/groove back to non choke ~bore/ groove size

https://www.gatewaytoairguns.org/GTA/index.php?topic=119504.0

Great suggestion, K.O.! I will certainly try it before I shorten the barrel.

YEMX · « **Reply #234 on:** August 19, 2017, 02:00:01 AM »

A more expensive option would be to use the TJ .25 Auto liner those BBT's were designed for. Probably not the answer you were looking for, but there have been many shooters who have had great accuracy using the TJ liner...

YEMX · « **Reply #235 on:** August 19, 2017, 10:36:12 AM »

I believe the barrel specification is: TJ's .25 ACP liner .250 groove, .243 land, 14" twist.

rintafile · « **Reply #236 on:** August 19, 2017, 10:43:18 AM »

Or try other models... Like this one

http://noebulletmolds.com/smf/index.php/topic,1897.0.html

calinb · « **Reply #237 on:** August 19, 2017, 02:42:23 PM »

Quote from: YEMX on August 19, 2017, 02:00:01 AM

A more expensive option would be to use the TJ .25 Auto liner those BBT's were designed for. Probably not the answer you were looking for, but there have been many shooters who have had great accuracy using the TJ liner...

I currently have a TJ's .257 barrel in hand, but need to fit it up. I got the TJ's 257 instead of the 25 ACP because I read so many reports of great accuracy from it--both with pellets and slugs, and even this 253-51 BBT mold that I'm using now. The reason I've tried so hard to get my 12" OEM L-W barrel to shoot accurately is I'd like to have both accurate short barrel and long 28" TJ's barrel options with the little TalonP carbine and I don't have my lathe at hand ATM to fit the TJ's barrel. The 12" OEM barrel might just have to be a Predator pellet barrel, because it's the only projectile that I've found to shoot

Quote from: YEMX on August 19, 2017, 02:00:01 AM

A more expensive option would be to use the TJ .25 Auto liner those BBT's were designed for. Probably not the answer you were looking for, but there have been many shooters who have had great accuracy using the TJ liner...

Wasn't the BBT 250-51, which reportedly drops 1-1/2 thou over print spec (driving band at .2535), made for the .25 ACP barrel? I have the slightly wider BBT 253-51 (driving band dropping at nearly .257 for me). I pushed one of my 253-51 slugs though my TJ's 257 barrel and both the lands and grooves were nicely formed or at least wiped at exactly .250 and .257, like TJ's specs it, so I have high hopes for the combination. I might still order a 257-65 BBT NOE mold for it though.

Quote from: rintafile on August 19, 2017, 10:43:18 AM

Or try other models... Like this one
http://noebulletmolds.com/smf/index.php/topic,1897.0.html

Yes. I probably should have bought that mold instead of my RCBS 25 ACP mold, which I have to "beagle-up" with .004" of tape on both mold halves and this process I devised to eliminate finning:

http://castboolits.gunloads.com/showthread.php?336649-De-finning-A-Beagled-Mold&highlight=beagle

At the time I bought the RCBS mold, I didn't know how non-standard "25 cal." air rifle barrels could be!

rintafile · « **Reply #238 on:** August 19, 2017, 03:35:35 PM »

That NOE's .25 acp mold group buy is still open. It needs 10 singned before it goes to mill. So You have change to get that mold if You want.

K.O. · « **Reply #239 on:** August 19, 2017, 05:46:18 PM »

I have yet to see a good report with the RCBS .25 acp mold... I wonder if hogging out most of the grease groove would help...

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.25 cal 51 gr. NOE Bob's Boattails

Author Topic: .25 cal 51 gr. NOE Bob's Boattails (Read 43050 times))