RCBS 145SIL nose size die

[Intheshop]

Keeping paralysis by analysis at bay,figured what the hey.... what's the worst thing that can happen? It don't work? Learn from this one and make another....

Took an hr, a letter J drill,and a 5* tapered reamer. Utilizes the little jewelry C frame arbor press. Normally, this press is used for initial GC install on a variety of sizes of bullets.

Interestingly,looking at first pic,that op is now combined in with the nose size... and sorta didn't see that coming. Horseshoe engineering.

Other than hitting my Mark's on the machines.... not a whole lot to say. Pics should explain it all. After sizing,you flip it over and a pin presses bullet out through the bottom (hole goes all the way through wood base).

 

[Intheshop]

 

[Intheshop]

Results

 

[fiver]

could you feel that little bit of parabolic shape on the nose by hand before sizing?

 

[Intheshop]

Don't know what you mean Fiver.

I'm on the last 50 or so bullets from a cast,a month or two ago. What's left is a bit regect'y.....

Not really going after any new loads with these. Just "throwing" 18.8g H4198 through the Accumeasure.... am checking visually with a maglight for height of powder in cases before loading but,NOT weighing diddly. Further,not weighing bullets or culling....grab N go.
Allows me to work on fit,independent of other distractions. The load is a good'n,leaving powder charge alone helps identify what effects other aspects have. Seating depth,neck tension,bullet fit,etc.

Then,when casting some real nice bullets here in a few days... I should have a solid feel for what the bullet "needs". And will get back to better GC on all processes. Just a backdoor approach.

 

[S Mac]

Maybe he mean that the nose sizer didn't size further down, toward the first band.

 

[Intheshop]

A taper is a wonderful approach to things. You get to control diameter/s with the depth.

Not saying it's the end all.... but,it is noticeably different than usual parallel sizers. The compression is different as well,but I can't explain this aspect very well. But it is real....

 

[Intheshop]

This,as cast nose in this particular barrel throat is just,by a few .0001's "over" what's prudent from an,ejecting loaded round dimension.

I can "play" with the sizing depth in a taper form and then match it up to the seating depth.

 

[Intheshop]

Have had this 5* reamer for 30 years,still sharp as a well,reamer. This one is a made in U.S.

You can find them on ebabe for taper reaming guitar bridges.

 

[Intheshop]

Oh yeah,I have an adj "straight" reamer in this size as well. They can be reground and/or manipulated to pretty much create whatever your little heart desires..... also available on the cheap from the bay.

 

[Ian]

Fiver was asking if your as-cast bullet already had a taper where you sized it since the rest of the nose appears to have a slight concave, parabolic taper.

 

[Intheshop]

As cast,it's a straight nose up to just before the drive band where there's a very short taper.

 

[fiver]

okay.

I have a couple of molds that I would swear on a stack of bibles had a little 'bulb' out on the nose.
that wasp waist shape is called a parabolic shape [like a foster slug has]
anyway you can feel it between thumb and forefinger more than measure it.

I have often thought about having a mold cut that way as one of those 'hundred dollar tests' just to see how things crumple, and just what it would take to barely make them do it versus trying to slam everything back until it filled the cylinder.

 

[Intheshop]

Allright,little update;

First off,the brandy new Timney 512,2# trigger that got installed yesterday is not a little easier to shoot groups with.... it is night and day easier. I have a 510 on my ADL 223 but that rifles factory trigger was SO gooped up with locktight that there was no adjustment available. Meaning,that Timney got installed before the rig ever made to the bench so to speak. This 7-08 factory trigger was adjusted to 3 1/4# and have been blasting,and killing varmints with it for a cpl years..... cast only.

The new 512 is ridiculously badarse!

OK,that out of the way.....

The load is still,thrown 18.8g H4198....not weighed. Chitty,cull,bttm of the batch 145SIL also not weighed,grab N go. The only difference is they're being nose sized and regulated on "depth" of nose size by measuring off the bullet base to top of size die. Refer to 1st pic above.... the present method is just,OK. What's needed is a sleeved depth stop but,that comes later. Right now it's being measured. They chamber with great ease and precision(more on this later).

First thing to show up,"on paper" was group moved up(no scope adj) 1 1/2 moa. Next thing is there is a small- med amt,of more blow back showing up on fired case necks. And I don't or can't quite explain this one.... gotta ruminate on it for awhile? Previous loads saw durn clean fired necks.... well within tolerance levels. Heck,these new loads aren't bad.... only mentioned cause of the change. It is apparent. I'd also dare say the nose sizing caused a touch more recoil but that being a feel thing,isn't completely quantified.

Think beer can plinking/killing.....With some of the worst QC'd bullets I've ever shot,these nose sized 145SIL aren't about "just" hitting the cans. You can put them in the drinking hole @100..... one right after another.

 

[Intheshop]

I've seen moulds with tapered noses. Well,maybe not in person but pictures and prints from manufacturers. I sort of "got it",along with tutelage from the brain trust here on "Artful". What I didn't get was the ease of setting OAL to get the loaded round's bullet all snuggly on chambering.

And here lies the beauty of taper nose sizing an "oversized",as cast nose. Not only,do you get the ease of snuggin the fit but,now its independent of the as cast,base to ogive measure..... tough for me to put that into words. Let's try it again....

If you have a tapered bore rider that casts "X",base to ogive you get; one setting on your OAL that is,in tune we'll say. When you start to manipulate WHERE that taper is,referenced from the base,you now can seat the body of the bullet independent of where the taper interfaces with leade.

 

[Ian]

You did two things at once by sizing the noses: Seated the bullets longer and reduced engraving pressure.

Seating them longer reduces peak chamber pressure and extends the peak down the barrel a little bit and reduces velocity, ergo longer barrel time and higher POI.

Reducing engraving pressure (and to a certain extent the longer seating) delays peak pressure until the bullet base is past the case mouth, giving the powder gas room to get around the case mouth before the real pressure comes on and forces the case neck to obturate the chamber wall.

 

[fiver]

yep.^^

I think your starting to see what we were advocating earlier.
not the whole entire concept but the basic beginning of why and how to make the next step past the medium speeds and keep accuracy consistently over a long string of shots, and not just the cold barrel happies.

 

[Intheshop]

I understand folks shooting in competition,which would put emphasis on strings of fire. I also understand that there are certain inherent problems discussing hunting in today's PC climate. At this point in time,and will say,subject to change..... the goal is not strings of fire. It's about hitting a Ghog squarely between the eyes with a cold bore. Further non PC'ness.....the more,"fine red mist", the better. Hence the velocity. To the point that finite accuracy can sometimes take a back seat..... and that isn't without due consideration. If,what I figure out is of some use to a competition leaning shooter,cheerio mate,have at it.

Compression,from a material and work hardening standpoint.... before,during,and after as it applies to a CB sizing and subsequent launching is an area I haven't seen addressed.... thoroughly. It gets touched on here N there. How a CB "mushrooms" on impact only describes a reaction,from a work hardening standpoint. And for some,that's plenty enough,dead is dead. But the act of traditional "sizing" a bullet..... something I'm prone to,not do... does what to the surface hardness? And how does this then,effect changes in the "tune". Cause my gut is telling me nose sizing,in the way prescribed above,ain't all about fit.... even though it accomplishes that quite nicely. Comment or no.... probably should be in a seperate thread later.

 

[Intheshop]

In a recent thread about bench blocks. They are delrin.Did you know,or maybe stated better..... do you know, the difference in using a std twist drill vs an endmill or forstner "bit" for punching holes in the stuff,as it effects the holes dimensions.

Do you need to know why there's a difference? Or is it enough to know the difference and plan accordingly?

 

[Ian]

HV concept is real simple: Get the bullet into the bore absolutely straight, and get it all the way through the gun so it comes out of the muzzle with a balanced form.

The methods and materials you choose to use to get it from case neck to target make all the difference. Obvious enough? Maybe not. Break it down, ALWAYS think of it as an integrated system, visualize the interactions and confirm with observed clues. What are you looking for? Anything which aids accomplishing the HV concept. Hint: The areas of particular interest are DYNAMIC fit, powder, and alloy, and a few other basic details which any accomplished handloader is probably already doing, such as bushing neck dies, in-line seaters, etc. Drawing the bullet noses is part of both static and dynamic fit, you have observed the results of that change, and that line of study (alter FIT, observe results) can be continued with altering seating depth, slight changes in alloy temper or composition, neck tension, and so forth.

Compression,from a material and work hardening standpoint.... before,during,and after as it applies to a CB sizing and subsequent launching is an area I haven't seen addressed.... thoroughly.

You haven't seen much on it because lead alloy doesn't work-harden, it work-softens.