Bullet modification

Burning some midnight oil. . .

Made initial setup to mod 350 SMKs.

Tried some several innovations to chuck up the bullet and get consistent trim length. First couple didn't work well enough.

Third attempt is a winner. Will refine the process to decrease time per bullet while maintaining consistency. Have to machine a gizmo. That's the pits as I'm no good at machining.

Cranked out the first brass tip. It's gonna be much easier to machine these than for the Nosler bullets. Still have problems with cutting tools. My HF cheapies really suck. Gonna have to burn up some time and rod and learn how to create consistent cutters. Once ground they last a long time with brass but still have a life expectancy that isn't for ever. . .

First bullet assembled looks good, runs strait but is a little on the rough side. But . . .

Overal bullet length increased by 0.145" and final weight is 356 grains.

I figure I can lose 6 grains and be satisfied with the original 350 as long is I can maintain the length increase.

The project's priorities are first to increase terminal performance at ELR ranges and second to increase bc.


Nightie Night and Merry Christmas to ya'll. . .
 
Roy,
Can you post up a photo of the bullet with its new brass tip?

I think HSS is better for cutting brass and copper. Got to get the speed right up there also for a good cut.
 
Topshot,

Here's some pics.

This is the "first" tip and first 350 SMK trimmed and fitted. A little rough.

Much time has been spent since these were made truing the lathe, learning to grind cutters and learning tons about angles and fit.

Most things are figured out with the hardest part learning to get machining of the shank precise enough for the critical press fit. Patience isn't my long suit but we're getting there, sort of. . .

The Alum tipped bullet is a Hensen made 338 285 grain offering using what I think is the Corbin Alum tip.

The brass tip is a taper developed for the 270 cal attempts I did.

I'm using that same taper but an angled base in an attempt to enhance expansion.

When I used this design on Nosler 150 BTs they became explosive on impact when compared to factory bullets. A tip base perpendicular to the shank produced terminal performance pretty much identical to factory.

The brass tip as shown weighs 11.1 grains.

Here's pics.
 

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Roy......what is the base of your tip in dia? They look a lot like my .175" brass tips only the bevel on yours is a little sharper than mine. I only went with 15 degrees. I just wanted enough to get them started expanding out instead of in.....rich
 
royinidaho said:
If I would have thought ahead I would have done differently but the bbl that came available when it was time to buy was a 10 twist. Which may well limit the heaviest bullet to the CE 375 grain offering.
Click to expand...

I wouldn't be too concerned about the twist rate & "only" being able to shoot the 375s.

I have found that yes the 425 is the best one to use for ELR but the 350 is only a small amount behind & very capable.

Because of their bore rider design, as the BC goes up, the velocity goes down at about the same rate.

This is different to conventional designs because the bearing surface is the same on the projectiles from 350 to 425

This means that you have a few projectiles to choose from with out handicapping the LR performance, as long as the twist rate is such that they will stabilise.

I tipped the CEBs ages ago to increase their terminal performance.



I also found that even if the tip looked a "little average" & weights weren't completely perfect they still shot extremely well even at 2000 yards.

I did lose a little BC even though the speed went up, they impacted 2 moa lower at 2050 than the standard 425s which was still much better than the 414 GSC.

The new Lazers should mean I don't need to do this anymore which is fine by me as I'm a little lacking in the patience department when it comes to tipping lots of projectiles
 
Roy,
Those tips look great.
Its another option for those with patience.
I like the way it keeps the weight up compared to the aluminium Corbin tips.
 
Great Stuff…

I wish Corbin would make there punches and dies a lot faster.. I was hoping to get them soon, in order to stay busy while I wait for my Raptor LRSS rifle. but who knows…

Great Info…

Happy New Year
 
It's been a while and filled with all kinds of hick-ups. A machinist I'm not. Having said that I'm learning a ton.

Went back to square one more than several times. Darn near gave up twice that many times.

The lathe I bought several years ago for $375 is now up to nearly $800. On a good day, for turning a tolerant patient fella could get $150 worth out of it.

If I could learn to properly sharpen/shape a cutting tool the other half of my woes would be taken care of. Carbide tips suck on brass, that's for sure.

Today it finally came together a bit. I have 10 that I consider worth shooting. Only messed up 4 others. Not bad considering how things were a year ago. :roll eyes:

Average weigh of the 10, including the extremes is 351.7 with run outs from 0.0015" to 0.011". Throwing out the 0.011" run out the average is 0.0065.

The run outs between 0.0015 and 0.005, 6 of them, we'll see what they group and POI shift compared to the 350 SMKs.

I've had to innovate a seating device which works quite well. The basis for it is a Wilson trimmer base. Next thing will be to make a new ram for the Rockchucker and do away with the plastic mallet. :roll eyes:

The original point design, shown in earlier posts, has been completely revamped.

ALSO, if a good hard look is given to the ogive of the SMK I'm pretty confident fractures will be noticed in addition to the normal crimping creases. I found if the tip shank was cut much over 0.002" overside, what looks to me like a longitudinal stress fracture appears when the tip is seated. It's been several decades since I dealt with die penetrant and welding cracks and I wasn't very good at them. Nevertheless there's something funny going on.

Also, this whole idea isn't for the light hearted. I wonder if It's really worth it. . .

Here's the results compared to factory SMKs.
 

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Nice work Roy. I can't tell you how many times I've wondered why the heck I do some things but it all helps in the learning process. I give you a lot of credit for your ingenuity and perserverance. The bullets look pretty good; especially the one on the left........Rich
 
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