Neck Tension/Crimp

[littlejack]

You DO know that there is a difference between BORE diameter and GROOVE diameter.
Bore diameter will be about what yours is, +/- .001. Groove diameter will be .457 - 8 - 9.
What is the micrometer reading at the widest point (groove) of the slugged boolit?
"This will show the groove dimension of the barrel, NOT the groove of the slugged boolit".
Jack

[Gellot Wilde]

What bullet are you using and what weight is it...there is no mention of this unless I missed it?

[Ed in North Texas]

Yeh from what I've seen from you so far that about sums it up.

Gratuitous insults aren't what I expect to read on Cast Boolits. "Smiley", or not, I believe it wasn't appropriate.

Just my $0.02 USD.

Ed

[John Boy]

Bummer, preliminary findings were right.

For what it's worth, the bore & groove diameters for my 45-70 rifles:
449 - 4584 ... Douglas on a CPA 44 1/2 receiver
452 - 455 ... H&R BC
450 - 454 ... '73 Trapdoor
450 - 455 ... Pedersoli
449 - 455 ... Uberti HiWall
450 - 454 ... Pedersoli
Even the 45-75's are 452 land and 456 groove

Are you sure that the 0.452 is the groove diameter and not the bore diameter that you are measuring? The groove marks on the slugged bullets should be measured on the 2 high spots opposite from each other for a 6 groove bullet

Just got back from the range and Boomer (my Pedretti & Sons Sharps) had a miserable day

Presume the groups were poor. Which leads to this question - what bullet alloy are you shooting? If they are store bought bullets, does it say 1:20 or 1:30 on the box? Possibly could they hard cast bullets for smokeless reloads that are Lyman #2 or harder in the range of Bhn 18?

[TXGunNut]

Thanks for your interest, guys. I think we're getting somewhere. Just knocked another slug thru to be thorough.
Bore diameter .452"
Groove diameter .459-460"
Alloy used Sunday 50/50 clip-on/stick-on WW's, air cooled for at least a week. Have used commercial 20-1 and 30-1.
Used Lyman 457122 (Gould 330) and 457193 (405 FP) Sunday, have used 457125 (500 RN) as well. All boolits weigh within 2 grains, heaviest to lightest.
(Used 457193 over a smokeless load in a Guide Gun to fire a 2.5" group, another load development project in progress.)
Most recent loads used a .060" wad. compressed FFg charges .070" after dropping thru a tube.
Boolits drop just a hair over .459 from each mould, 50/50 closer to .460. All recent boolits run thru a .459 Lyman sizing die, lubed with SPG.
My concern with neck tension is likely a hangover from rifles using sp and j-word bullets, I try to keep my smokeless thought processes away from the BP processes but it's difficult. I want the tension to be uniform. I'm planning on taking this rifle hunting someday so I'm not too comfortable with little or no neck tension.
And yes, Ed, I felt that seemed a bit rude but I figured (hoped?) they were having a little fun.

[RMulhern]

HOT DAMN....in 20 years I haven't learned a damn thing!!

[John Boy]

I think we're getting somewhere. Just knocked another slug thru to be thorough.
Bore diameter .452"
Groove diameter .459-460"

Finally, 2 pages later! Whew! OK, your on the hunt of understanding. Believe your measurement of the groove diameter is on the high side. Measure a couple of more times. So, what you need to buy now is an expander die and expander plugs so the neck tension is 0.001 to 0.002 smaller than the bullet base with a bullet that is 0.001 to 0.003 larger than the groove diameter
Track of the Wolf:
Expander Plugs, buy them all ... 457 to 462... http://www.trackofthewolf.com/Catego...Support=1&as=1
Trust me, no 45-70 bullets are exactly the same sized base

Neck Expander Die ... http://www.trackofthewolf.com/catego...=LEE-DIE-45-EX

* Measure the base diameter of the bullet to be reloaded
* Put the proper size plug in the expander die
* Expand the case neck with a bell wide enough so 1/2 of the bullet base sets in the case
* Charge the case and seat the bullet ... a crimp only to remove the bell
That's it, your done except for buying a good reference manual on reloading lead bullets.

Here's a free read ... http://www.wahsatchdesperadoes.com/I...CR_Loading.pdf

This should be the end of the thread ... Good Luck Shooting

[TXGunNut]

Sorry, John Boy. Didn't mean to keep you in suspense. Measured the groove diameter several times, dial caliper not the best tool for the job but one set of grooves consistently measured .459, another .460 and the other was a bit rough but it was in that range. I have the .459 plug and the Lee Die, seems I need a .458 and .457.
I have Venturino & Garbe's BPC Reloading Primer, Lyman's 4th Edition CB Handbook and Lyman's BP Handbook & Loading Manual. BP cartridges aren't covered very well in the BP Handbook but have read the other two pretty thoroughly.
Any thoughts on powder compression, John Boy? Consensus I'm getting is a rather profound "it depends on the rifle". Kinda reminds me of sp and j-word bullets.

[RMulhern]

Short lesson!

Unless you're shooting a '73 Trap Door Springfiled.....and you wish to shoot a grease groove bullet....cast a slug of .459" and size it to .458" and fill the grooves with a BP lube! If your bullet is .458"...use and expander plug of .456"!! Seat the SOAG such that the OAL engraves about 1/2" of the first drive band and you're good to go! If PP....shoot a bullet that will give you a finished bullet OD of .447" to .449"; one that's easy to chamber and an alloy of 1-20 or 1-40 and you'll get good results.....provided you pay attention to the ironclad rules of marksmanship!! I can't stress enough how good NORMA brass works!!

[TXGunNut]

Thanks, RM. I think you and John Boy have given me a neck tension solution I can use for hunting. Will order plugs but also want to try the loose fit method many of the BPCR comp guys seem to like. Dropping a boolit into a charged case with no neck tension seems very odd but if I don't try it I'll never know.
Only been shooting BP cartridges about two years and it seems the first rule of BP should be "This Ain't Smokeless!"

[Don McDowell]

On tight chamber rifles like the Winchester bpcr's and Shiloh you need to flare the case mouth just a tad , and then the bullet just falls in, then crimp just a tad so the round will chamber.
You're right it does take some getting used to loading that way.
Sure saves alot of wear and tear on the sizing die..

[TXGunNut]

That's what I did tonight, Don. Just skipped the sizing step, flared it just a bit to get the boolit started and "crimped" it just enough to chamber it. Seated the boolit mostly to get the wad to a uniform depth. Seems odd but hard to beat this method for uniformity. Will hopefully have a clearer picture this time tomorrow. Maybe I'll still get some use out of my sizer die next time I buy new brass.
Ordered the .458 and .457 Lee sizer plugs as well as taper crimp and neck sizer dies for my Guide Gun loads. Somehow Venturino's book on "Shooting Leverguns of the Old West" made it into my cart as well.

[Don McDowell]

I resize my brass after 3 or 4 firings, or when you feel a marked difference in chambering ease. So you may not want to use the sizing die for a slip sinker in your fishing tackle box just yet.
Looking forward to seeing how this works for you.

[TXGunNut]

No danger of any dies becoming slip sinkers, Don. I have no idea what it'll take to make these rifles shoot and I'll be sending a check to our friends in Big Timber when I figure out what I want in my next Sharps. It'll be a .45-70 but have no idea what that rifle will like. I also think any new batch of brass needs a trip thru a FL resizer.
I appreciate the tip, Don. Was wondering when this brass would need a FL resize. I'm wondering if my Hornady dies overdo the resizing thing. Tomorrow (today)'s going to be fun!

[Don McDowell]

My Hornady dies size the cases down a bunch tighter than my Lymans do.