I've heard of, but never seen, dies which will slightly increase the diameter of a bullet. I'd like to "bump" some .277" bullets up to .285" and am wondering if anyone knows where such a bump die could be obtained, or if you have a design for one which could be built?

What bullet do you want to bump? Isnt .285 ordinary 7mm.

Yes you could do it with Corbin dies, but why? Best to sell your 270 bullets and buy 7mms. The cost of the die won't be cheap and your resultant bullets won't be as good as factory ones.

I should have stated the reason in order to allay the obvious question of "why?".

I have a 7x33 Sako for which bullets are mostly unavailable. In factory form it uses a roundnose 78 grain bullet of around .285-.286" diameter. Its magazine is very short and won't accept the shortest 7mm bullet commonly available. Nosler has just come out with a blunt-nose 90 grain bullet in .277 for the 6.8mm cartridge. It might work fine in my little 7x33 if bumped to .284-.286".

Now, how can I accomplish this?

Call Corbin; Google them up; they will tell you how and sell you the tools with which to do it. Corbin is the biggest and probably oldest, bullet swage tool company on earth.
It's www.corbins.com

http://www.ch4d.com/

F. Guffey

CORBIN Swage Dies. $$$ as in very.

I don't find any "bump" dies listed on either the Corbin or ch4d websites.

I recommended to call them and ask. They can answer all your questions.

Corbin mentions using a point forming die for bumping bullets to a larger diameter.

http://www.corbins.com/pf.htm

You guys sound like my daughter; "I can' t find it on the web so I don't know what to do".
I guess I am old school; if I want an answer, I call them and speak to a human. Amazing technology, that telephone..

I tried changing the nose of .358 220 gr flat nose bullets to spitzer several years ago and the jackets ruptured forcing lead into the
rupture. I'm sure these bullets would be unbalanced and I don't think the bullets would be very accurate.

I would think bumping up a bullet would probably cause the same issue, only more severe.

Has anyone every bumped up a bullet successfully?

Yes, I bump up .500 pistol bullets to .510s for my 50-95; works fine but as you pointed out, there is a limit to how far you can go. All bullets are made by bumping up to some degree so in principal, it will work.

Several suggestions:

slug the bore and get a flat point bullet mold that drops a bullet of the groove diameter + 1 1000th. Cast it of pure linotype and you could push it to 2200 only 200 less than the fmj original.

Speer makes a 115 gr FBHP & Sierra a 100 FBHP that could be easily faced off in a lathe to meet your OAL.

Raptor makes a 115, just cut it off from the back and don't use the tip.

If you go on the net, there is a photo that includes a 7x33 loaded with a a 110 Speer TNT, so I guess it worked in something.

Having a machinist make a tapered swage to reduce the diameter of a 30 caliber pistol bullet like the Sierra 85 gr 7.63 Mauser bullet would also be an option.

I'd go with the linotype option as it's simple and an 85 gr 7mm flat point will certainly kill anything a 115 gr 32-20 going 1/2 as fast will.

can you go the other way and swag 8mm .318-.320 down to .286.

I have some 85gr jacketed (may be plated) nambu bullets. Not sure what will happen to the jacket.

Huntington and buffalo list them

Much easier to swage a .308 bullet to .285 than starting with that's 10 to 12 thou larger.

"Having a machinist make a tapered swage to reduce the diameter of a 30 caliber pistol bullet like the Sierra 85 gr 7.63 Mauser bullet would also be an option."

It is entirely feasible to use a standard jacketed bullet nose-form die to bump bullets up 5-10 thousandths in size. I have done it for years with complete satisfaction.

The bullets one ends up with are every bit as good as any other factory cup 'n core bullet....maybe better. As the bullet is bumped up, the lead core is expanded inside the cup (jacket). As the jacket has some springiness to it, it tries to spring back to its original size when the bumping is complete. Of course it can't spring back because the lead has NO spring to it. So basically, the jacket ends up being even tighter on the bullet core than before.

So the "new" bullet made from the old one has just as much physical integrity as the original one did, if not more.

I have made and shot thousands of 150 and 170 grain spitzers (both .3085" and .311") from very old .306" diameter .30-30 RN bullets made by CIL (Dominion brand). And before someone shouts that .30-30 bullets are not .306" diameter...well, modern ones aren't, but back in the very early 1900s they WERE.

It is really very little different from putting a bullet just taken afresh from the core-seating die and running it into the 'point forming die' when making Benchrest bullets.

And I just use a RCBS Rockchucker press for most of mine. It doesn't require much pressure to expand a cup 'n core bullet a few thousandths of an inch.

I don't even know what make my .30 nose-form dies are...I bought them used on-line for $50 apiece delivered to my door.

Yep; what he said. Swaging down does not usually work as well (I have done that too) as the lead will compress more than the jacket which will spring back, leaving the jacket loose. So more than a few .000 will not work for reducing. Going up is another matter. If you call Corbin, they will tell you al this and more.

Stonie,

I'd try another method; you won't compromise the jacket or the lead core.

Try some .284" Sierra 100 gr. Hollow Points since they're about the shortest commonly available 7mm bullet and put 'em on a lathe or Drill Press and cut the noses down. 120 gr. bullets for the 7-30 Waters that are Flat Points probably require too much taken off the front end. Dunno?

Lathe is the easiest. I used a hard nylon piece of round stock that was laying around my tool bench from some completely unrelated POS and simply drilled a small "Cup" into one end of it until @ 3/16" or 1/4" of the bullet base would pop into it. Basically a plastic jig.

This leaves the bearing surface the same length and alters the ogive but the .366" bullet I use shoot perfectly.

Or use a Wood Drill @ 3/8ths or 5/16ths, (the ones with the little pointy sharp bit on the end) surprising what kinda shapes you can come up with on the bullet nose(s). I've modified a couple of the inside edges of wood bits with Dremel Tool bits to obtain the shape I desire.

With these I've "modified" a bunch of the 270 gr. Speer .366" vanilla-flavored Cup 'n Cores into a nifty 250 gr. sorta "Hollow Point" using this method.

The hickup on a Drill Press is getting 'em centered to start.

Anyway, you could probably get those 100 gr. Sierra .284's HP's down to <85 grains without "modifying" them, too much.

I'm sure all those dedicated bullet maufacturers out there consider I'm a tad daft; but I've been called worse.

I agree; lathe cutting down the noses will be much cheaper than buying dies, and should work. Good idea.

Cutting cup & core bullets in a lathe is not a way to keep from compromising the bullet structure, IMO.

Swaging up does not compromise their structure.

How are C'NC bullets made? By seating a core which is significantly smaller in diameter than the jacket into the inside "cup" of the jacket, then using a "core seating" die to make sure the core is bumped up to where it fills the inside of the jacket, from the base forward. The cup/jacket is not squeezed into shape at that time.

Then the final diameter of the bullets and the shape of the nose are made by shoving the cylindrical cup and core into a "nose-form" die. Adjusting the die determines whether you get a soft point or a hollow point, if you are making spitzer nosed bullets. With other shapes, drilling may be done if one wants hollow points.

Weight of the bullets is determined by the weight of the core added to the weight of the jacket.

And so, using an existing bullet to bump up in diameter while retaining the weight of the original bullet is pretty much just like using the cylindrical cup & core of an unshaped bullet in the point form die. With either, the final squeezing determines point form.

The major differences are that using existing bullets means one doesn't need a core-seating die or separate cores. Saves cost of a core-seating die, and the time/effort of using it.

Plus one knows the cores of the original bullets have been professionally & correctly seated.

The construction of the "new" bullets formed are in no way compromised as far as their integrity. Or at least no way more than making the original bullet compromised the cup and core of it.

quote:

Originally posted by Jgrabow6493:
I tried changing the nose of .358 220 gr flat nose bullets to spitzer several years ago and the jackets ruptured forcing lead into the
rupture. I'm sure these bullets would be unbalanced and I don't think the bullets would be very accurate.

I would think bumping up a bullet would probably cause the same issue, only more severe.

Has anyone every bumped up a bullet successfully?

What you got with the .358 bullets sounds to me like what IBM customer service politely calls "operator error"...either the wrong tools or wrong techniques. It is no stunt at all to reshape the noses of any C'nC bullet of the same diameter if one uses the correct nose-form die.

Are you sure you weren't trying to bump "bonded" bullets? That is more tricky.

quote:

Cutting cup & core bullets in a lathe is not a way to keep from compromising the bullet structure, IMO.

A-C.

O.K., I'll just have to agree to disagree on this one.

I just got done cutting down some bullets for my 500 NE; shot fine, fully as well as the 570s do. No one told me it wouldn't work. Because it did.

Im not familliar with the 7X33, but it doesnt sound like much of a velocity monster. Maybe you should look into some hard cast bullets. That would be far less financialy prohibitive than a swaging setup for a single, odd calibered rifle.

quote:

Originally posted by Stonecreek:
I should have stated the reason in order to allay the obvious question of "why?".

I have a 7x33 Sako for which bullets are mostly unavailable. In factory form it uses a roundnose 78 grain bullet of around .285-.286" diameter. Its magazine is very short and won't accept the shortest 7mm bullet commonly available. Nosler has just come out with a blunt-nose 90 grain bullet in .277 for the 6.8mm cartridge. It might work fine in my little 7x33 if bumped to .284-.286".

Now, how can I accomplish this?

quote:

Originally posted by metalbeater:
Several suggestions:

slug the bore and get a flat point bullet mold that drops a bullet of the groove diameter + 1 1000th. Cast it of pure linotype and you could push it to 2200 only 200 less than the fmj original.

Speer makes a 115 gr FBHP & Sierra a 100 FBHP that could be easily faced off in a lathe to meet your OAL.

Raptor makes a 115, just cut it off from the back and don't use the tip.

If you go on the net, there is a photo that includes a 7x33 loaded with a a 110 Speer TNT, so I guess it worked in something.

Having a machinist make a tapered swage to reduce the diameter of a 30 caliber pistol bullet like the Sierra 85 gr 7.63 Mauser bullet would also be an option.

I'd go with the linotype option as it's simple and an 85 gr 7mm flat point will certainly kill anything a 115 gr 32-20 going 1/2 as fast will.

I sometimes think we are so eager to get our post done that we never read what has come prior in the thread.

I don't know where the idea came from that swaging down a NON BONDED cup and core softpoint is going to loosen the core. That how they are made in the first place, a jacket with a piece of lead rod in it, shoved into a forming die. It a'int rocket science.

You mean swaging UP, not down. That is how bullets are made. Swaging down too much will loosen the core as the copper jacket springs back more than lead will. Swaging up makes the core tight.

Can only assume you are not old enough to have ever made .223 bullets for the Hornet by Swaging using 22RF cases and lead rod.

62.
You still have to force the core into the jacket and not just swage it down. That causes loose cores, although I have swaged some bullets down, like I have made 9.3s from .375s, back when we could not get any 9.3 bullets. And I have swaged .429 bullets down to .412.
I also make .510 bullets from .500s by bumping them up.
I think that you might not fully understand how factory bullets are made.