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Tight neck questions

PostPosted: Sat Jun 30, 2018 9:31 am
by CJP1
I have been going through the Reloading for the 450b older posts. On page 21, there was talk of resizing the case to help hold the FMJ .451 bullets. Is there any one here using that technique along with the taper crimp? Do I need to tight neck resize for the 200gr and/or the 275gr Barnes XPB's or will the crimp into the driving band be enough? Also there was mentioned that they were using the 45LC sizing die to resize the case where the .451 bullets will be seated. Would it help to use the Lee taper crimp dies instead of the Hornady as I already have one? Thank you for your help.

Re: Tight neck questions

PostPosted: Mon Jul 02, 2018 7:10 pm
by CJP1
I just got done pulling bullets to see how just the taper crimp worked on the 4 bullets I loaded in unprimed brass. All bullets came out much easier than antisipated.
* Barnes 200gr XPB crimped into front driving band. Three hits with the kinitic bullet puller.
* Hornady 240gr XTP MAG crimped at the cannelure. Two hits.
* Barnes 275gr XPB crimped into forward driving band. Three hits.
* Barnes 275gr XPB crimped into center driving band. Three hits.
The mouths were crimped to .475. It doesn"t seem like there is enough tension, especially on the 240gr XTP. I think that I'm going to try this tight neck method. I don't know if it will work with the 240gr XTP MAG bullets or not. I might have to go back and bell the case mouth before seating them.

Re: Tight neck questions

PostPosted: Mon Jul 02, 2018 8:09 pm
by Hoot
If you have the Hornady seating die, it will guide the bullets in, even with the Tight-neck-Taper applied, as long as the mouths are chamfered. No need to bell them as that defeats some of the advantage for the tight-neck. CJP, when you say "into front groove", did you mean seated so the mouth drives down into the almost buried groove? That gives it the greatest hold. Ditto on "at the cannelure", did you mean with the bullet seated so the cannelure was almost buried and drove the mouth down into the cannelure? That's the way I got them to hang on the best. None of these methods are totally inertia proof. Smooth sided bullets are a real challenge. All Hornady does is taper crimp the mouths down to .478 !!! This caliber is not for repeated chambering. :| BTW, in bullets with two grooves or cannelures, never use the rear one as it doesn't leave a caliber's width down in the case IIRC. Also, you don't want to distort the heel of the bullet in the least bit. Its the last point of contact with the bore. Remember, the case still firmly headspaces at .470 (actually less). Its all a matter of just how much you want to distort the bullet.

Hoot

Re: Tight neck questions

PostPosted: Wed Jul 04, 2018 9:48 am
by CJP1
Hoot,
Thanks for your answers to my questions. I didn't use the expaner die when I seated those bullets. I didn't know if I would once case mouth was narrowed. I crimped the three Barnes bullets with the driving band groove buried and just peeking from in front of case mouth. I did the same on the Hornady cannelure. The 200gr crimped in the front groove.The 240gr crimped in the front cannelure. The 1st 275gr crimped in the front groove. The 2nd 275gr crimped in the middle groove. It looked like the one with the 275gr crimped in front groove wouldn't leave much room for the powder.

Re: Tight neck questions

PostPosted: Wed Jul 04, 2018 10:31 am
by Al in Mi
On those 275gr, you can run them about 2.410 oal in that rar, leaves a bit more room for powder.

Buddy suppose to be coming up this weekend with his rar, going to run it along my #1 for accuracy with those 275gr barnes.

Re: Tight neck questions

PostPosted: Wed Jul 04, 2018 6:44 pm
by CJP1
I'm going to pick up a solid steel rod to go into my Lee 45LC sizing die. Then I'll be able to able to narrow up the cases more closely to length of bullet seating depth.

Re: Tight neck questions

PostPosted: Wed Jul 04, 2018 10:21 pm
by Hoot
CJP1 wrote:I'm going to pick up a solid steel rod to go into my Lee 45LC sizing die. Then I'll be able to able to narrow up the cases more closely to length of bullet seating depth.


Its been a while, but IIRC, I cobbled up a rod inside an old decapping die. The bottom line is that brass exhibits more springback than copper. In the case of cup ad core bullets, once the taper crimp is applied, the case springs back, even so slightly and always less than the copper does, so you're always playing against a "stacked deck". I thought the TNT solution would be the manna from heaven, but it didn't help with velocity SD's on lighter bullets, like I hoped it would. There's little left to do outside of putting a stab crimp on them. I am loathe to do so, but its the only thing I've seen work, at the cost to group sizes a little.

I spent the last few days trying to get a replacement for my recently deceased, 20 yr old Craftsman riding lawn mower before my lawn requires a machete. Search teams are trying to find a group of Malaysian kids lost in my lawn. It being peak mowing season up here, puts one in a bad position for bargaining, assuming you can find what you want in stock. Gonna get a zero turn one this time, so perhaps it'll roll over on me less. Not fun crawling out from under a mower in the farmer's hay field, then pushing it up the hill. I'm getting to old (read out of shape) for that crap! ZTR's aren't cheap, especially the better brands. Hope to pick one up tomorrow. Had to mooch the neighbor's low trailer. The Craftsman cadaver is in the back of my F150, which a guy at work is taking for parts. That's my excuse for not getting the range reports done. ;)

Hoot

Re: Tight neck questions

PostPosted: Thu Jul 05, 2018 10:52 am
by CJP1
Hoot,
Thanks for the insight on the TNT. I thought it would be the end all to keeping bullets secure in the brass. I'll see about using a little more crimp. I don't really want to go with the stab crimp unless I have to.

Re: Tight neck questions

PostPosted: Thu Jul 05, 2018 11:30 am
by Al in Mi
Has anybody gave feedback on Lee's factory crimp die where it crimps on the mouth?

Re: Tight neck questions

PostPosted: Thu Jul 05, 2018 7:51 pm
by Hoot
CJP1 wrote:Hoot,
Thanks for the insight on the TNT. I thought it would be the end all to keeping bullets secure in the brass...snip....


So did I. sigh...

It's not a reach to realize that heavy crimping distorts bullets giving them a waspish figure. At least the cup and core ones. The less appreciated damage is what happens to the case mouths. The mouth is where the case wall is the thinnest. Repeated heavy crimping there thins them even more, leading to a vicious cycle or needing more crimp, causing more thinning, needing more crimp. causing more thinning, etc. the Thinning is not in leaps and bounds, like squeezing a rolled up ball of chewing gum but it does happen, especially with solid copper or solid brass bullets. Its a cumulative effect. That's why any opportunity to crimp down into a driving band groove or cannelure is a saving grace.

Al, I seem to remember someone reporting on their experience with a 450b Factory Crimp Die right at the mouth.

I've also experimented with using a resizing die as a taper crimp. The reason you may have not noticed a report on that was despite doing the job, it provided no benefit that I could tell. Somewhere I have some target scans of the groups. IIRC, they were on par with groups provided by a taper crimp die. Certainly didn't help with velocity SD's either. Try the resizing die sometime yourselves. It works.

About the only thing I have yet to try is sealing compound like Markron sells. According to them, it doesn't effect pressure, so never felt like giving it a try.

Hoot