Making a Bump Die

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  • Last Post 08 July 2017
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OU812 posted this 28 January 2017

I made a bump die, bump die stop and removing stem from  machinable 12L14 steel.  . Die and die stop fits closely inside a hollow LEE case flaring die. The matching NOE nose stem acts as a stop inside die while RCBS press cams over exactly on each bullet. Bullet is compressed about 1/32” for good results. The hollow tip of removal stem was filled with JB Weld and cured to bullet and then to protect nose during removal. Mc-Master Carr supplied the .220 and .227 reamers...very fast shipping. .2205 diameter is also available.  

The pointed NOE 80 grain bullet is undamaged and more uniform diameter entire length of bore ride section AFTER Sqeezing larger

 

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Ken Campbell Iowa posted this 08 July 2017

pretty convincing target !    thanks ...

hey are we getting hacked by horses now ?? ... i didn''t catch his name ...

ken

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OU812 posted this 08 July 2017

Getting more bullets ready (72 grain and 82 grain) to test using different powder charges and different brand Gas Checks. 

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OU812 posted this 08 July 2017

Shot these groups today compairing as cast to bumped. This is the original design NOE 80 SP bullet shot from 1/12 twist Remington barrel. Gun has some throat erosion and likes a bullet bumped larger and more round to .2214.

Lapua cases, Lee Collet die, Winchester primer, Bullets sized .226 then lube in Oversized die with LBT soft blue, Hornaday gas check. Bullets were bumped with lube in grooves to prevent collapse.

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OU812 posted this 20 March 2017

I think the best barrel for this 30 cal. bullet would have Six grooves and 1-12 twist.

Two years ago I purchased a Bartlein —.30 5R 1:11.25 Twist 26” Finished, #7 MTU 1.20” x 2.75” tapering to .930” Barrel. This barrel was on sale, so I pulled the trigger. Now I am trying to decide what chamber to go with...300 Savage or 30BRX?

The 30BRX is similar to the 30BR except the shoulder has been fire formed longer, neck slightly shorter. This allows for slightly more powder capacity.

I will go shoot the 223 Remington tomorrow. After more carful measuring bullets had to be squeezed to .2215 diameter to engrave rifling when chambered.

I may purchase this Remington 700 chambered in 308 NATO (#84207), 1/12 twist, six groove rifling. I said NATO because all 308 Remington's use the larger NATO chamber (.311 diam. freebore, .186 diam. length). This rifle is also available in 223 Remington 1/9 twist 20” barrel...lots easier to shoot also.

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OU812 posted this 20 March 2017

Squeezing rounds more round...is that a felony? Actually the fresh cast linotype (not aged hardened) is easier to extract from die after squeezing and forms to die just as good or better than softer alloy.

BTW Hornaday One shot case sizing wax works better than Redding Imperial wax...smells like wheel bearing grease.

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Ken Campbell Iowa posted this 20 March 2017

thanks ou for finding that you can swage/bump linotype successfully ...

i remember back ~ 1985 when bumping was ok but swaging was a felony ... that one reason given * against * was that you couldn't swage harder bullets anyway .

which seemed funny in that cast bullets seem to be  deformed easily enough when we shoot them ...  ( g ) ....

my efforts back then in swaging from lead blanks was with * hard ball * ::  taracorp magnum alloy ... seemed to swage just fine ... the trick is enough leverage and give it a few seconds to move in the die .....

ken

new barrel, EH ? ... keep us informed, this should be good .   learning learning learning ...

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Scearcy posted this 20 March 2017

OU812

What bullet did you start with?

Jim

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OU812 posted this 20 March 2017

Linotype is so much easier to cast with. Here are a few 30 caliber bullets I bumped just right after casting. Bullet on far right is not bumped and sized.

Bore ride section now measures a round .3003, bands measure .3098. These are waiting for new barrel to be installed

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OU812 posted this 10 March 2017

NOE nose sizers are crap. You must make a smaller diameter larger to work.

I ordered my 30 cal. Accurate mold slightly under size so that bullet could be squeezed larger to targeted diameter of .3000. Accurate molds is the only mold maker that makes custom diameter sizes.

My .223 has a larger throat which is why bullets can be bumped (squeezed) larger and more round.

 

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OU812 posted this 10 March 2017

Maybe bump it, take it out, rotate it 180 degrees and bump again?

 

You will need to squeeze down the bullet to correct. Much like my method using matching nose punch (ouch).

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OU812 posted this 10 March 2017

I have never liked  that collecting groove ahead of front drive band...I think that is a weak point.

John has it correct with this bullet. Short band area and long bore riding surface. I love this picture...could you imagine scaled  up 6mm, 6.5mm versions

Remember to use tight neck clearance.

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Tom Acheson posted this 10 March 2017

Maybe bump it, take it out, rotate it 180 degrees and bump again?

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OU812 posted this 10 March 2017

Tom, Notice the offset parting line of your bumped bore riding bullet. That is were the problem lies. Bump that area more round to fit bore and bullet well shoot even better.

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Tom Acheson posted this 10 March 2017

Interesting...my Savage .308 really likes bumped bullets a lot more than non-bumped bullets. This has worked pretty good in CBA Production class events. Maybe someday I'll focus on that rifle instead of my XP-100.

 

Tom

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OU812 posted this 10 March 2017

I believe no tapering of any kind is needed. Bullets need to be more round to shoot...much like jacketed bullets are more round. Bumping in non tapered die makes them more round and inline.

Although a more tight case neck to chamber wall helps. The savage has a tighter neck clearance than the SAMMI 308 Winchester.

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Tom Acheson posted this 10 March 2017

I assemble the rounds to be about 0.025” longer that the developed OAL. As the bolt closes it pushes the bullet back into the case. This gun will never see a jacketed bullet. However, I had some prairie dog rifles that shot better with the (jacketed) bullet about 0.010” off the lands, 6 BR, 70-grain bullet. This is something every rifle needs to explored with to determine the best loading condition. So far all of my match CB guns prefer the “jamm” approach when using bumped bullets.

 

Tom 

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OU812 posted this 10 March 2017

Yes, seat bullet long so that it is against or pushed back into case by front band against forcing cone.

I have been thinking of chambering a barrel in 300 Savage so that the longer seated bullets will clip feed from 308 Winchester well. The SAMMI 300 Savage has a long free bore (.167 long) diameter .3095 diameter.

The best thing about bore riding bullets is that throat mods (tapering) are not needed to make them shoot and you can still shoot jacketed like the rifle was intended to shoot in the first place.

 

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Tom Acheson posted this 10 March 2017

Another bullet bumping experience.

 

This is a Saeco #264 bullet for a 6.5mm chambering. Weight is about 133-grains in 50/50 lino/mono. In both photos,  the lower photo, the one on the left is not bumped. The one on the right has been “bumped”. You need to look real close but the start of the “bumping” is about half way between the bottom of the lube groove and the top of the gas check. This slight bumping taper continues up the ogive to just short of the bullet’s nose. Odd, but the groove above the lube groove appears narrower on the bumped bullet.

When looking at the loaded rounds, upper photo, note how much further out the bumped bullet is seated on the right. These lengths are determined by seating a bullet only in the chamber and then measuring the OAL. This right hand assembled round is just about where I’d like it to be, with only the gas check and a small portion of the area above it in the case.

One of the objectives of the “bumped” bullet design is to get the bullet up into the throat area as far as you can and hopefully end up with a “cone in a cone” relationship between the chambered bullet and the throat area.

Now to wait for decent temps to get out and shoot!

Tom

 

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OU812 posted this 10 March 2017

made the nose punch by first drilling a .170” diameter hole .230” deep (11/64” drill bit).   Next I cut angle using the tiny boring bar set to15 degrees per side (30 degree included angle). Bore scope helps check work while cutting. All tools purchased at McMaster Carr

 

 

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OU812 posted this 10 March 2017

I made another die and nose punch for the custom “undersized” 30 caliber bullet. The as cast bullet bore ride section measures .298 before bumping. After bumping in the .3000 diameter die, bullet's bore ride section measures a rounder .3004 diameter.

As the guns throat erodes and grows larger after many shots, just hone the die larger to fit.

Bullet tip is now more uniform and slightly smaller after bumping.

Be sure to seat these inline or as concentric as possible with case (under .002 run out). Looser neck tension will allow you to adjust.

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