Gen II Henson .338 265 grain project and performance test #1

Status
Not open for further replies.
Gents, here is a partial quote:
"
I was just fooling around trying to get a starting point and lucked up on what may be a pretty good load. I only fired 11 rounds, nine out of this gun and two out of my 300wsm. (300wsm didnt like them, keyholes) got a lot of verticle out of the hotter loads but 64 grs gave me 2 side by side w/n 1.5 inches at 800. I drove back to the reloading room loaded another round and put it within an inch of the other 2. I suspect that a 1.5 inch group at 800 is about as good as I will ever shoot with basically a sporter weight gun. So yes I will say the bullets will probably shoot, it may have been luck I will let you know tomorrow, with a bit more powder burned."

I am hung up on our use of the correct twist for these bullets and the keyholing found above just verified. Again to get the loooooonger bullets stabilized, the twist must be nuts on. Period!!!!!! Contact Lawton Machine for specifics. Overbore
 
The gun they keyholed in is a kreiger 13 twist I think. You know those benchrest builders are going to go with the slowest twist for a specific bullet. Don Geraci set the gun up to shoot 168s, which it does into little bitty holes:) I just thought I would give it a try since it will stabilize 208s okay.

BTW I was concerned with these bullets coppering my barrel because of the rough finish. Seems my concerns were totally unfounded. I let the barrel soak in Butch's while I started playing with my 338, no blue whatsoever after a 40 minute soak. Now if I can just get the 265gr 338s to shoot.



Gents, here is a partial quote:
"
I was just fooling around trying to get a starting point and lucked up on what may be a pretty good load. I only fired 11 rounds, nine out of this gun and two out of my 300wsm. (300wsm didnt like them, keyholes) got a lot of verticle out of the hotter loads but 64 grs gave me 2 side by side w/n 1.5 inches at 800. I drove back to the reloading room loaded another round and put it within an inch of the other 2. I suspect that a 1.5 inch group at 800 is about as good as I will ever shoot with basically a sporter weight gun. So yes I will say the bullets will probably shoot, it may have been luck I will let you know tomorrow, with a bit more powder burned."

I am hung up on our use of the correct twist for these bullets and the keyholing found above just verified. Again to get the loooooonger bullets stabilized, the twist must be nuts on. Period!!!!!! Contact Lawton Machine for specifics. Overbore
 
Following quote from LV

"Now, the Gen IIs have a much less bearing surface and they can be pushed about 249 fps faster than the 300 SMK AND as a bonus they have a much higher BC as indicated by the significant differences in drop we saw"

"the bulletsmith modified the bullets to use some of the aerodynamic design and technology employed on our Submarine launched ICBMs"

question.....

I don't really care about subs shooting BM's.... other than bearing surface length was there any jacket/core/tip changes made that will make this a reliable hunting bullet with suitable expansion at lower velocities?

I recieved some gen I test bullets and shot them in my 338/378, with the limited amount of testing I did not find any horrific change in group size, I also did not shoot them at a distance to test drop against the SMK. I am sure everyone would like to have a working 265 but the combative nature of these threads makes it hard...... What alloy is the AL tip? If it was a softer AL maybe it would flatten instead of turn sideways? What has been tested? Have you tried different jacket thicknesses? Just hoping to get back to a technical solution for some lighter 338's!!!!

The differences between the Gen 1 and the Gen IIs are just the geometry of the bullet profile. They will not expand at reduced velocities with reduced gyro stability spin and they are not designed for slow cartridges. When launched at full velocity potential for the cartridge, you will find that they expand very well. With the unaltered design of the jacket, a launch speed of 3000 fps should suffice for proper expansion. For those wishing to launch at slower speeds, then the tip would have to be modified internally to promote expansion at slower muzzle velocities. They will work at reasonable starting velocities...... Just let Mr Henson know at what muzzle velocity you are expecting to shoot them.

The aluminum tips have been tested in various hardnesses. Again, if the launch speed and spin are correct, this bullet will drive right through the target as posted on the various meat tests.

The test conducted by shooting at a significant reduced initial velocity also initiated minimal gyro spin. When the bullet contacted the target, it did not have enough stability to drive through. Had the test been conducted at the yardage that was being simulated, then the results would have been different since the gyro spin would not have decayed to the starting point of the reduced velocity testing.

On the Jackets, we have only tested the current jacket thickness. Again, they expand predictably and reliably when lauched at the proper velocity and spin rate.

On your group sizes, I don't have enough information to be of much help other than the following procedure (which we previously published here and also on the reverse of the bullet invouce sheets) that we use to tune loads:

We went about the load development of these bullets in the same fashion as we have in the past will all the bullets we have tested (ie GS customs, Lost Rivers, Sierras, Noslers, Swifts, Wildcats and Bergers). Specifically, we conduct a pressure test of the selected powder charges at -.030 off the lands and then slowly increase the powder charges until we reach the point that satisfies us and provides good brass life. We call this the -.030 pressure test.

After the pressure testing, we take that EXACT same powder charge and then test it for ACCURACY at -.030, -.040, -.050, -.060, and -.070 off the lands (with Davidson Ogive Tool and micrometer seating dies) and as a side note, we ALWAYS use a mirage shade to minimize mirage influences due to the barrel rejecting heat. So far in the many tests of all of the above bullets, a load or loads have surfaced that would allow the harmonics of the barrel to work in concert with the powder charges, cases, primers, bench equipment and shooter to yield tiny groups.

Note: when we identify a loading, we then shoot it several times to verify the results. Additionally, when a seating depth is identified, we then shoot it again along with bullets seated +.005 and -.005 from the identified seating depth and that will give us the range of the sweet spot so we can load for the center of it vice just the extreme edges. The final loading is tested for accuracy at 400 yards as well during the 400 yard zero process.

If this does not help, call me on my company phone 678-882-6575 and I will be more than willing to help you.

Lightvarmint
 
Gents, here is a partial quote:
"
I was just fooling around trying to get a starting point and lucked up on what may be a pretty good load. I only fired 11 rounds, nine out of this gun and two out of my 300wsm. (300wsm didnt like them, keyholes) got a lot of verticle out of the hotter loads but 64 grs gave me 2 side by side w/n 1.5 inches at 800. I drove back to the reloading room loaded another round and put it within an inch of the other 2. I suspect that a 1.5 inch group at 800 is about as good as I will ever shoot with basically a sporter weight gun. So yes I will say the bullets will probably shoot, it may have been luck I will let you know tomorrow, with a bit more powder burned."

I am hung up on our use of the correct twist for these bullets and the keyholing found above just verified. Again to get the loooooonger bullets stabilized, the twist must be nuts on. Period!!!!!! Contact Lawton Machine for specifics. Overbore

Hello,

Just to clarify the requirements for stabilization of the currently available bullets:

.338 265s and 280s require 1-10" twists

.308 210s and 220s require 1-8" twists

.308 180s require 1-10" twists.


Lightvarmint
 
Great! Now we know what is required for twist and my further kudos for posting your load development procedures. This should get accuracy and expansion questions on a solid footing.

Well done.and thanks. Overbore
 
Great! Now we know what is required for twist and my further kudos for posting your load development procedures. This should get accuracy and expansion questions on a solid footing.

Well done.and thanks. Overbore

I believe that Mr Henson always gets the specifics from customers on their shooting irons prior to selling bullets. I know some folks have wanted to test the .30 210s in 1-9" twist barrels, but that is not the recommended twist for the bullets. However, you/we shooters are free to experiment as you/we see fit.

Lightvarmint
 
I believe that Mr Henson always gets the specifics from customers on their shooting irons prior to selling bullets. I know some folks have wanted to test the .30 210s in 1-9" twist barrels, but that is not the recommended twist for the bullets. However, you/we shooters are free to experiment as you/we see fit.

Lightvarmint

My calculations call for a 7.8 twist for the 210's so I must be using a different SG but, for those who think this is Greek, we are close enough to go try. Best, Overbore
 
Status
Not open for further replies.
Top