That looks like an awfully long boolit. What is the minimum twist rate required for subsonic stability?
That looks like an awfully long boolit. What is the minimum twist rate required for subsonic stability?
I haven't tried this one yet, but I have a 1 in 8" twist that stabilizes 220 gr Matchking bullets just fine. I would imagine this should stabilize with the 1 in 8".
Yep, you'll see small marks on each bullet where they contact the screen during baking. No surprise, and no big deal. A second coat helps (I do 2 coats on all of mine); and some powders are worse than others for sticking to the screen.
This 230gr 300 AAC bullet is an odd one. It can be improved quite a bit by getting rid of the boat tail base. On mine, I removed most of the boat tail, but left a gas check shank on the end, since I use it in my AR. Hollow pointing seems to improve the accuracy a bit, as well as making a huge difference in terminal performance. This bullet, like most heavy .30 cal subsonics, gives pretty limited terminal performance without a hollow point. Even with a pure lead nose, my testing shows little or no expansion, and no tumbling on impact, just a tiny hole punched straight through. The hollow point performs more like a typical handgun hollow point bullet though.
Reaming out the boat tail to a plain base is easy enough with a drill press and a .311" or 5/16" reamer. Leaving the gas check shank intact, though, requires doing the operation on a lathe with a small boring bar, which is what I did.
Didn't think of you using a lathe. I've only read of boring out the whole boat tail in a drill press. Makes perfect sense now. Thanks.
What's the benefit of converting it to gas check base vs just crimping a check onto the boat tail like a few people said they were doing? More accurate or better retention or are you just crossing t's and dotting i's?
Retention of the gas check is the same, but the longer driving band on the base seems to make it more accurate. I also wanted to increase the driving band diameter a bit, and figured I might as well get rid of the boat tail. Also, I don't use bullet lube any more, so I didn't need to use that area for lube.
Incidentally, I screwed up the driving band diameter (measurement error) and it drops at .320" now. I'm still powder coating and then sizing it down in one step, with great results; the oversized band doesn't seem to matter at all.
I wasted allot of time trying to get the Lee TL309-230-5R to shoot in a Remington Mod. 700, 300 AAC caliber with a 7:1 twist barrel. After a couple failed attempts, I examined some of the sized bullets and noted that the land located close to the middle of the bullet and just ahead of the lube grooves did not touch the LEE .308” sizing die. I then measured this area of the bullet with calibrated micrometers and found them to be ~ .305” diameter. The bullets were cast “correctly,” that is “filled-out” in the molding process with crisp “lines” that matched the mold. I have been casting rifle & pistol bullets in other calibers - .357, 44 & .45 - with success for several years and own 11 other Lee molds.
Based on my measurements, I believed that the bullet diameter was undersize so I contacted Lee Precision. The mold, along with some sample bullets, were sent back to Lee Precision for examination. After about a week, I received the mold back, unmodified, with a note from Andrew Lee stating the reason for the undersize condition was the use of “Drop out” spray, and that I should use the “match-smoke” method to coat the mold with carbon. I’ve used this method in the past, before purchasing the Franklin Arsenal Bullet drop spray.
I’ve then cast more using the “match/smoke” method. It added ~.001” to the average diameter measurement of the lube groove lands. However, the very “front” (raised area just ahead of the lube grooves) of the lands still have no or minimal contact with the .308” sizing die. What surprised me were the dimensions listed on the Lee Precision inspection form. It indicated the wide land in the middle of the bullet (the area I thought was undersized) is only .305” diameter BY DESIGN! When the tapered “boat-tail” length of .21”, plus the front groove which is ~.04” long, subtracted from this bore contact length, it leaves less than ¼”length to support and guide the bullet down the rifle bore. And what does engage the bore in this short length are angled, thin lands with an as-designed contact surface of only .010” wide. In effect, there’s very minimal support for such a long bullet, and it’s all located in the back 1/3 of the bullet’s length.
I am not a bullet designer, however, common sense tells me there is not sufficient support on the bullet’s front end to reliably guide this bullet down a rifle bore shot after shot. I have read that adding a “gas check” will help accuracy. Probably because it adds more support to the bullet’s contact area with the bore. However, this bullet is not a “gas check” design bullet. If a gas check were attached it would be on the tapered section of the bullet, unsupported in the powder area of the 300 AAC cartridge case, and prone to dislodge. I am unwilling to try this.
After spending much time and effort attempting to get bullets from this mold to work with some degree of accuracy, I’ve concluded that this design, for any kind of reliable accuracy, is simply not serviceable. I have since returned the Lee TL309-230-5R to Midway - hats off to them - they took the used mold back and credited me full purchase price! I have since bought a NOE 240 gr. and it works great.
I get good accuracy with this boolit–shoot them as-cast in a 16" AR carbine with an MAS 1/8 barrel. The bore is .307", that helps. I think it's an interesting design too.
can you give some detail on how you make them hollow point.
I saw a test where it did tumble a fare bit but no expansion I want expansion but dont know how to make them hollow point.
I was thinking of using this as a moose round eventually.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |