Bullet modification

[royinidaho]

Thanks for the support guys.

Visited with my machinist buddy this afternoon. He gave me some pointers and and a decent carbide bit. It cuts like butter. I think it'll take things up a notch.

Have to rework the chuck jaws as the brass rod can stick out of the chuck so far before it becomes too flexible. The steady rest was a waste of money. A steady rest with bearings straight across from the cutting tip is necessary but difficult to come by.

Will do some shooting tomorrow. Then some point making and bullet prep and see if we can get consistency enough to get out towards 1k. When that is accomplished we'll do some drop and terminal performance comparisons with the unmodified SMKs.

 

[elkaholic]

Thanks for the support guys.

Visited with my machinist buddy this afternoon. He gave me some pointers and and a decent carbide bit. It cuts like butter. I think it'll take things up a notch.

Have to rework the chuck jaws as the brass rod can stick out of the chuck so far before it becomes too flexible. The steady rest was a waste of money. A steady rest with bearings straight across from the cutting tip is necessary but difficult to come by.

Will do some shooting tomorrow. Then some point making and bullet prep and see if we can get consistency enough to get out towards 1k. When that is accomplished we'll do some drop and terminal performance comparisons with the unmodified SMKs.

The shooting test will be VERY interesting Roy! I took some 200 gr. SMK's (.308) and ran them through my rebated boat tail/vld dies one time and they shot very well. Of course that didn't solve the REAL problem with them, and that is, they don't expand reliably......Rich

 

[royinidaho]

Should have had a report of some sort today. Got one check shot off w/unmodified SMKs then a couple of fellas showed up with all kinds of rifle/reloading problems.

Maybe tomorrow. . .

 

[Deleted member 46119]

The shooting test will be VERY interesting Roy! I took some 200 gr. SMK's (.308) and ran them through my rebated boat tail/vld dies one time and they shot very well. Of course that didn't solve the REAL problem with them, and that is, they don't expand reliably......Rich

I am intrigued, what is your setup. Press and die.

I talked to Corbin about this same thing. He didn't like the idea. I wanted to do it with .338 285gr Hornady BTHP.

 

[royinidaho]

I am intrigued, what is your setup. Press and die.

I talked to Corbin about this same thing. He didn't like the idea. I wanted to do it with .338 285gr Hornady BTHP.

There are a bunch of things Corbin doesn't like. However, if ya wanna do it it's your money.

I wanted to swage 7mm Bergers to 277. He said the odds were against me but we went ahead anyway as there was a probability that it may work. And I was desperate. He was correct. It didn't work. But was fun anyway and didn't set me back too much.

I don't think you'd gain very much though. The RBBT doesn't add all that much compared to a standard long boat tail.

But, hey how will one ever know unless ya try. But then again, experience is the best teacher . . . as long as it's someone else's experience.

 

[Bullet bumper]

A rebated boat tail has no advantage over a smooth boat tail.
The reason a rebated boat tail exists at all is that it is the only easy way to make one in hand press and die systems. If you try and make a smooth transition boat tail then the edge of the base forming punch is so thin on the edge it will crack and flake under pressure so they step it in a bit to thicken the edge and it creates a step in the edge of the boat tail . The real clever part is they then make up a c*ck and bull story of how it's a special design meant to be that way .
I make my own bullets and have for many years and this is an interesting thread but If I was doing this type of thing I think I would want to true up the meplat insert with the ogive in a die of some kind maybe even give it a bit of an ogive bump up without bumping the shank diameter .
This way the junction of the cone and the start of the jacket might be much better inline . Any ridge in that area could start an uneven shock wave that may or may not affect accuracy but it could increase drag .

 

[elkaholic]

I am intrigued, what is your setup. Press and die.

I talked to Corbin about this same thing. He didn't like the idea. I wanted to do it with .338 285gr Hornady BTHP.

I used Corbin dies and press. I don't know why it wouldn't work. Changing caliber might be de difficult but I had no problem with simply changing the ogive shape from a tangent to secant. Those presses exert 50,000 to 60,000 psi. I didn't mess with it too much because I make my own tipped bullets that I like a lot better (Go Roy)! They did shoot very well though.........Rich

 

[royinidaho]

I'm learning some stuff.

Not an authority on this at all. Whatcha see is whatcha get.

What I learned today is:

+ My ability to keep track of stuff sucks. Remembering important stuff costs me.
+ Bullet seating depth trumps bullet tip wobble. By a ton!

I loaded 3 unmodified 350 SMKs as a check group. They did at the rigs accuracy level.

I loaded 3 modified tipped RBTs (Roy's Brass Tips ). These were the best out of round bullets. Under 2 thou runout. Hmmm, shot slightly over 1 MOA @ 300 yds.

Loaded 3 more modified bullets. A little worse runout. Hmmmm, again shot slightly over 1 MOA.

Ah Ha, then I remembered. The tipped bullets seat deeper than the unmodified ones. The seater touches the brass about 10 thou up from the tip base. Duh!!!

Seated my last 3 modified bullets to the correct base to ogive length. Well, what da ya know??

What impressed me most was that these tips were gross to look at when looking with a critical eye. Run out for each bullet was 0.0065", 0.008", and 0.011" Hmmmmm!!

Gonna fab some more and go to the next step.

My media is frozen solid. Guess I'll bring it in the house, thaw it out and mix in some antifreeze. No way I'm waiting till spring to check drop and expansion.

 

[elkaholic]

I'm learning some stuff.

Not an authority on this at all. Whatcha see is whatcha get.

What I learned today is:

+ My ability to keep track of stuff sucks. Remembering important stuff costs me.
+ Bullet seating depth trumps bullet tip wobble. By a ton!

I loaded 3 unmodified 350 SMKs as a check group. They did at the rigs accuracy level.

I loaded 3 modified tipped RBTs (Roy's Brass Tips ). These were the best out of round bullets. Under 2 thou runout. Hmmm, shot slightly over 1 MOA @ 300 yds.

Loaded 3 more modified bullets. A little worse runout. Hmmmm, again shot slightly over 1 MOA.

Ah Ha, then I remembered. The tipped bullets seat deeper than the unmodified ones. The seater touches the brass about 10 thou up from the tip base. Duh!!!

Seated my last 3 modified bullets to the correct base to ogive length. Well, what da ya know??

What impressed me most was that these tips were gross to look at when looking with a critical eye. Run out for each bullet was 0.0065", 0.008", and 0.011" Hmmmmm!!

Gonna fab some more and go to the next step.

My media is frozen solid. Guess I'll bring it in the house, thaw it out and mix in some antifreeze. No way I'm waiting till spring to check drop and expansion.

Way to go Roy! I have also found that the tips can be out of whack a little with no apparent accuracy loss. I learned early on not to tumble (polish) bullets after you put the tips in. The only really bad luck I had with this was, one got so loose it came out ahead of the rest of the bullet and made a nice little triangular shaped hole through BOTH of my skysreens.....Rich

 

[Kiwi Greg]

Way to go Roy! I have also found that the tips can be out of whack a little with no apparent accuracy loss. I learned early on not to tumble (polish) bullets after you put the tips in. The only really bad luck I had with this was, one got so loose it came out ahead of the rest of the bullet and made a nice little triangular shaped hole through BOTH of my skysreens.....Rich

I also found when I tipped the CEBs that even the " so ugly I wouldn't give it to my Mates" projectiles still shot just as well as anything.....

I guess it is because the tip is in the centre axis & has very little influence over precedings ?

Very nice shooting Roy.

 

[Bullet bumper]

That looks quite good . The small amount of extra drag would be cancelled well out by the BC increase of a much smaller meplat tip . There may be some extra shock wave from the not perfect fitting meplat inserts but that may not affect lateral . The canular in a military projectile will cause an added shock wave but it don't seem to make spin drift worse .
The only thing is that Corbin's ballistic tips are expensive .

 

[elkaholic]

That looks quite good . The small amount of extra drag would be cancelled well out by the BC increase of a much smaller meplat tip . There may be some extra shock wave from the not perfect fitting meplat inserts but that may not affect lateral . The canular in a military projectile will cause an added shock wave but it don't seem to make spin drift worse .
The only thing is that Corbin's ballistic tips are expensive .

Not only are they expensive, he went from a 5 gr aluminum to a 14.5gr mild steel which didn't do much for sg.......Rich

 

[Bullet bumper]

True but if the target is anything to go buy the stability looks ok . So moving the center of gravity forward does not seem to be an issue at that range so far .

 

[elkaholic]

True but if the target is anything to go buy the stability looks ok . So moving the center of gravity forward does not seem to be an issue at that range so far .

Agree with that. I was thinking more in general. For some of the long bullets that I make, it is not a plus. I think Roys bullets are a little smaller and lighter than Corbins too............Rich