.224 cal Bullets Revisited

[rsterne]

I am revisiting some of the information I have collected on .224 cal swaged bullets for long range airgun use in this thread.... rather than sidetrack another thread.... First of all, Sean Pero and I received some samples from Holland of the bullets they are using.... I ran the dimensions through the Border Barrels Twist Calculator, and here is the information....



Photo above is a 39.5 gr. bullet of 0.223" diameter.... Graph below shows the stability factor in a 16" Twist barrel as used in a .22LR....



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Photo above is the 41.5 gr. RWS airgun bullet as used in the Drummen Sinner, achieving groups as small as 12mm at 100M (0.4 MOA).... It is 0.224" diameter, and as near as we call tell, it is based on the RWS R-50 .22LR target bullet.... The graph below shows the stability factor in a 14" Twist Hornet barrel.... This is the barrel I chose for my Hayabusa, and it is chambered for these bullets.... So far, I have achieved a peak velocity of 1077 fps, and a practical string of 10 shots averaging 1030 fps with a 2% ES.... which will yield a tethered velocity of 1040 fps at 2800 psi.... Unfortunately I have not had the opportunity for long range accuracy testing of this combination as yet.... 



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The photo above is the 63 gr. bullet being experimented with in Holland.... It is 0.224" diameter, and requires a much faster twist for stability.... The graph below shows the Stability Factor using a 10" Twist barrel as would be found in centerfire PBs....



The part of the stability curves that interests us is to the left of the discontinuity which occurs at Mach 1.... Note that the bullet is the least stable at just below the speed of sound, and for these shapes the stability increases as the velocity drops below that.... This is less pronounced with the 63 gr. because of the Meplat.... All three examples show "just" enough stability at high subsonic velocities with the twist rates chosen.... A Stability Factor of 1.5 is considered about the minimum, the Military typically use 2.0 to 2.5 to allow for the effects of cold weather and high altitude....

A typical .22LR bullet, at subsonic velocities, has a Ballistics Coefficient of about 0.100 to 0.150, depending on whose data you believe and the exact velocity of the tests.... Compare this to what are the best diablo pellets currently available, which have BCs that peak at maybe 0.040 but by the time they hit 1000 fps the BC may be less than half that.... and you can see what huge gains can be made if we can find GOOD bullets for our airguns.... Please note that none of the above bullets will fit in a standard airgun barrel, they typically have a groove diameter of 0.217"....

Bob

[Nomadic Pirate]

Would love to test the 39gr out of my Rainstorm,...where do you buy them bullets ?

[PakProtector]

I would not mind finding a set of drawings for .225 boolits from various molds so I can run them through the twist/stability program. I can come close scaling pix, but that is most troublesome. If I can get energy out of the 22 Marauder project I will be in the market for a 10" twist barrel to shoot the 55+ grain boolits...mandrel charge from TJ's is about equal to a full barrel, so I'd need conspirators...
cheers,
Douglas

and barrel changing driving me towards a thimble perhaps...hmmmmm

[Ribbonstone]

Nest time I fire up the pot (mostly with lead salvaged from pellet traps, so it's going to be softer lead) will run off a handfull of these;



LYMn mold, but milled the mold off to remove the gas check base and turn it into a plain based slug. Still use it in lite loads in a .22K-Hornet, but think it has possibilities in a PCP.

[rsterne]

We got all three from Holland as samples.... decided on the 41.5 gr. RWS and bought 1000.... not cheap with shipping!....

What weight does that shortened bullet work out to Ribbonstone?.... I find a completely flat (ie full diameter) base problematic when casting.... Regardless of temperature the base never seems to come put completely symmetrical (ie perfect).... My thought is why bother having a perfect crown if the bullet base exiting it isn't perfect as well....

Bob

[PakProtector]

On the 'perfect base' Bob, I got some Cu and Al gas checks to try with the '107 boolits. Not that there is any issue with 'em that I ahve seen casting a few runs, but I figger, wth, it will 'perfect up' the tail and may help with leading. Was reading about a shortened 257420 mold and a few folks who shot boolits out ov it found the base fill had to be exactly perfect or they did not fly well. I have a 225462 I am contemplating shortening to the middle of the last groove in attempt to deal with that effect. Or I may shorten up a second one in hopes of getting enough power to send it downrange fast enough...lol or maybe get a 10" twist Hornet barrel( and load Hornets for it ). 10" should stabilize up to 70 grains...hmmm and there I go thinking about powder burners again.
cheers,
Douglas

[willbird]

I have not cast a lot of 22's, but in tons of other calibers I have gotten good base fillout with a flat base. I am rarely if ever trying to cast with pure lead, I add a few % tin.

Small bullets can be tough to cast fast enough to get the mold blocks hot enough for good consistent fillout. One BIG help in that area is to take an old circular saw blade and lay it on an 8.95 walmart hotplate, then use this to pre heat the mold, and to keep it warm between casting runs, I toss ingots on it to pre heat while I'm casting, they go into the pot and the mold goes onto the saw blade :-).

I actually use 1/2" aluminum plate because I had some, but other folks have saw blades and they use them :-).

I personally do not care for bevel base molds because that sharp corner where the bevel exits the cavity is a very delicate feature.

Aluminum sprue plates can help with base fillout too.

Bill

[rsterne]

Douglas, I have a 257420, and asked Erik at Hollowpoint Services about removing the gas check shoulder, and he said "why mess up a good bullet"....

From the percentage of "less than perfect" bases I have seen, it would seem to me that a better solution would be to nose cast with a meplat.... I'm betting that overall such a bullet (similar in shape to the 63 gr. above) would be more consistent.... In addition, I'm becoming a believer in meplats of about 1/2 caliber or even a bit larger as having much better performance on game than a round nose.... The hollowpoints I cast based on the 257420 have wicked expansion, I'm hoping the gas-check shoulder will give a clean exit from the crown, regardless of whether the base corner is perfect or not.... time will tell....

Bob

[willbird]

Douglas, I have a 257420, and asked Erik at Hollowpoint Services about removing the gas check shoulder, and he said "why mess up a good bullet"....

From the percentage of "less than perfect" bases I have seen, it would seem to me that a better solution would be to nose cast with a meplat.... I'm betting that overall such a bullet (similar in shape to the 63 gr. above) would be more consistent.... In addition, I'm becoming a believer in meplats of about 1/2 caliber or even a bit larger as having much better performance on game than a round nose.... The hollowpoints I cast based on the 257420 have wicked expansion, I'm hoping the gas-check shoulder will give a clean exit from the crown, regardless of whether the base corner is perfect or not.... time will tell....

Bob

Point pour seems to be one of those things that SOUNDS great, but in real life offers no real advantage worth the more complicated mfg process.

Veral Smith has always advocated the use of gas checks for a more uniform base. Personally I dislike them for lower velocity uses due to logistics and cost per bullet.

Bill

[PakProtector]

Getting a good cut off seems critical too. I ran some 252435 through a .251 sizer( and some 25-050-RN ) and the sprue cut can push the base around enough that they don't clean up in the sizer. Not sure this matters more up front or not. It could also be me not waiting long enough for the hot lead to get hard enough as it cools( it is soft, ~2% tin ). A nose pour with proper sprue cutter has more boolit to push against in the form of the long( compared to a wee drive band ) nose profile.
cheers,
Douglas

[willbird]

I keep looking for entry level dies to swage plain bullets with no jackets, and I am not seeing a lot. Swaging is the answer to a very good bullet as long as WW metal is hard enough (and it will be).

I saw a vbideo of a very simple core mold in use that has no sprue plate atall, and is not a split die, you just pour and use an ejection pin to push the core out, they were making cores like crazy. The swaging die then bleeds them to weight and forms them to size and shape. If they can swage .224 bullets with 22 rimfire jackets on a normal reloading press a lead alloy or pure lead one should be no problem.

Corbins solution is a semi wadcutter design.
http://www.corbins.com/lswc.htm


Looks like about $200 though, maybe it is time to play with the lathe a bit :-).

Bill

[willbird]

Getting a good cut off seems critical too. I ran some 252435 through a .251 sizer( and some 25-050-RN ) and the sprue cut can push the base around enough that they don't clean up in the sizer. Not sure this matters more up front or not. It could also be me not waiting long enough for the hot lead to get hard enough as it cools( it is soft, ~2% tin ). A nose pour with proper sprue cutter has more boolit to push against in the form of the long( compared to a wee drive band ) nose profile.
cheers,
Douglas

Conventional 22 cast bullet designs probably have WAY too much lube groove action going on for airgun use. They do provide a handy way to discern if a bullet is filling out properly though.

Bill

[PakProtector]

Tom isnt making "pellets" anymore (darn shame) big $$ but a corbin die makes a fine pellet/bullet when you get the right size going.
http://web.archive.org/web/20010615225251/http://ns.connext.net/~pellets/mywebsite004.htm
John

anybody ever shot any of those? not seen any press on it yet. certainly nobody crowin' about how good they are....
cheers,
Douglas

[PakProtector]

Here is notice of a .480-long 22 boolit mold. Looks like Bob's but with a flat point. I am going to get in on a buy on this mold as soon as it is available...
http://castboolits.gunloads.com/showthread.php?184811-BRP-226-47-GC-Group-Buy-Coming-Soon
cheers,
Douglas

[PakProtector]

Here is notice of a .480-long 22 boolit mold. Looks like Bob's but with a flat point. I am going to get in on a buy on this mold as soon as it is available...
http://castboolits.gunloads.com/showthread.php?184811-BRP-226-47-GC-Group-Buy-Coming-Soon
cheers,
Douglas

When you get that going I certainly would like to try a sample few.
John

No problem...