Well, this is an idea that popped into my head several years ago when I was working with the old Wildcat Bullet company. My work load grew to the point that I really just put it on the backburner until I found out that Corbin started selling these aluminum tips. That really got the ball rolling.
Well, Over the past several weeks, I have machined up several collet fixtures to allow me to precisely mount bullets in my lathe at the shop and do the needed work to convert them for these tips in a precise and repeatable manner.
Was able to take a couple hours this afternoon and put all the theory into reality. The main reason for wanting to try this is mainly the fact that the 375 cal, 350 gr SMK bullet is really a pretty poor performer as far as expansion at long range. The reason is because its jacket is massively thick. I figured one of these aluminum tips would not only boost BC but it would also make BC more consistant and aid in expansion at long range. Anyway, just starting out working on this but the theory worked very well and here are some examples.
Both of these are 375 cal, 350 gr SMK bullets, one on left modified for the aluminum tip. This added 0.137" to the OAL of the 350 gr SMK and should make a significant boost in BC as well as expansion performance at long range.
This one also intereted me. I have always liked the Nosler Accubond but they tend to run a bit low in BC, especially in 375 cal. This is the 300 gr Accubond in 375 caliber. Modifying this bullet for the aluminum tip added nearly 0.200" in bullet length. This bonded core bullet with a much better BC will make it a viable option for the larger 375 magnums for long range use including in my 375 Allen Magnum loaded to +3400 fps.
Perhaps the one that interests me the most is the Barnes 375 cal 300 gr TSX. By modifying this bullet with the aluminum tip, it gains a massive 0.333" in OAL. The BC increase for this bullet should be huge by removing the massive meplat of the standard bullet. Plus, Barnes bullets tend to be poor expanders at true long range distances, this tip may eliminate that issue.
Next up I tried a couple 338 caliber bullets.
Here is the old war horse, the 338 cal, 300 gr SMK. Adding the aluminum top took the OAL of this bullet from 1.720" up to 1.840" and should help to boost BC a bit and also make BC more consistant from shot to shot. Expansion has never been a HUGE issue with this bullet in the larger magnums but this tip may allow the smaller 338 magnums to get better performance at that +1000 range.
Another Barnes bullet that really impressed me. The 285 gr, 338 cal TSX-TAC. This one modified with the aluminum tip made it the longest bullet made of all the ones I tried so far. The tip added 0.165" to the standard bullet with an OAL of 1.962" making this one, one of the more interesting ones for me to test at long range out of my 338 Allen Magnum loaded to 3400 fps or a bit more. Again, should get a good boost in BC as well as better expansion at +1000 yard ranges.
These were the first bullets I have made so far with my new collet system. Again, these bullets are machined to accept these tips, not swaged formed. I will be working on the following bullets as well to see what improvements can be made on them ballistically:
123 gr SMK
142 gr SMK
130 gr Accubond
140 gr Accubond
160 gr Accubond
175 gr SMK
180 gr SMK
180 gr Accubond
200 gr Accubond
210 gr SMK
220 gr SMK
240 gr SMK
I will also be working on some Barnes bullets in all of these calibers as well to see what they can turn out. You may notice that there are no berger bullets listed. The reason why is because their ogive design is a bit more aggressive then the ogive on these tips. The result would likely be a wash in BC with the smaller ogive but slightly blunter meplat. I may test them. The 300 gr Hybrid may benefit from a tip as far as expansion at long range from chamberings such as the 338 Edge, 338 Lapua an even my 338 AX where there have been some examples of pencil holing through big game at ranges past 1000 yards. This tip would certainly solve that problem.
Again, just starting, no bullets in the air yet. I have made up 25 of each of the above bullets for testing. When that will happen, not sure. Still lots of customer project rifles to get out the door but hopefully with spring here and longer evening day light hours, I can spend some after hours time on the range doing some more ballistic testing.
I am also going to test these tips in the Barnes TSX bullets in 416, 458 and 50 caliber. The tips used in these larger calibers will be a much larger tip design.
Should be interesting, stay tuned. It can be scary what a curious mind and a precision metal lathe can produce with a few sleepless nights!!!