Dispersion?

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.22-10-45 posted this 3 weeks ago

Yesterday was a rare Nov. day in Michigan..79 deg. and very light to calm wind..just had to take advantage and go shoot!  I usually have shot my Sharps Borchardt , Shillen barreled .22 Hornet at 100yds using cast..but decided to try it out at 50yds.  I remember thinking at this short range they should all group into 1 ragged hole.  Boy were my eyes opened.  My average group with cast in this rifle at 100yds is around 3/4" to 1"  Sometimes..(nearly 20 years ago) when I first started working with it I could get 1/2" to 5/8" but not every time.  I had the late Fred Leeth make up nose pour moulds in both gas check & plain base of same weight..based on the old Ideal 22636 design.  These have prooved to be very accurate.  I have a dbl. cav. Lyman 225415, which I hardly used because of the custom moulds..but this one really surprised me giving some smaller groups than the more expensive moulds.  I also tried the little early Ideal 225415..the 48gr. g.c.  This gave me 1/2" groups using 7.0grs. H4227.  About those 50yd. groups..instead of 1 ragged hole as I thought..I was getting 1/2" to 7/16"  a bit smaller than 100yds. but not that much. The 1 big improvement in accuracy came when I swagged a 3 deg. taper on 1st. band to match chamber leade angle & chamber so to contact or even engrave this band as action closed.  Try as I might..and I am weighing bullets and powder to .1 gr. tolerance I cannot seen to get below 1/2"..and nearly always wit a flier.  The one bullet that possible could achieve this is an Eagan MX22..now when shot as cast it groups about like all the rest..but size it down to .225 or .224 & swage back up to .226 in a Corbin bullet swage die I had made for my reloading press..I had various shaped nose punches made up..swagged to a tapered flatnose..the bullet takes on a new look.  grease grooves are quite narrower (filled with Lyman Super Moly before swagging) the gas check is perfectly flat & corners sharpened up square..I leave a tiny rad. on bottom edge of check.  I shat a 1/2" group but with 4 cutting into 1 hole.  But why?  Pope insisted a bullet was as perfect as it was going to get right from the mould.. I really don't think I am closing up any voids inside bullet with the modest pressure I apply.  The base and sides are very much improved though.  Why can't I get results like this with my precision nose-pours?  Heck, even that dinky early 225415 48gr. shoots like this when run swagged.  Any ideas?  I also have used Pufflon ballistic filler and it improves some loads and others not so much..This stuff never seems to end!

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OU812 posted this 3 weeks ago

What is your barrel's twist rate?

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OU812 posted this 3 weeks ago

Have you tried using softer 20/1 alloy and Titegroup powder.

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OU812 posted this 3 weeks ago

When bumping the bullet the nose should also be bumped and aligned so that it does not wobble...soft or hard alloy. Fit is king, but softer alloy is a little more forgiving.

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.22-10-45 posted this 3 weeks ago

Twist rate is 1-14"  As far as bumping..the bullets are swagged in a Corbin bullet swaging die..so nose is fully formed to nose punch shape.  I have tried alloys from 20-1 lead-tin up to Lyno.

I made up a tapered sizing die to taper front band to 3 deg. to match throat leade angle..this is adjustable for length and dia. of taper applied.  Bullets are seated using a Wilson straight-line chamber seating die with Sinclair micrometer head.  Haven't tried Tightgroup, but I have been using Vihtavouri N110...leaves bore alot cleaner than H4227 with excellent accuracy.

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OU812 posted this 3 weeks ago

I have had very good results using Titegroup with 62-75 grain bullets(softer alloys) in a 12/1 twist barrel. Never been able to get lighter bullets to shoot as well in my 223. I bet your 14/1 is a challenge. Try Titegroup with both soft cast and jacketed (52 grain sierra match)

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OU812 posted this 3 weeks ago

BTW I used 5 to 7 grains of Titegroup in my 223 for velocities under 1700fps. I am sure your smaller caliber will require less.

Vertical stringing will be non existent using TG.

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Wineman posted this 3 weeks ago

I did a little experiment of my own. I normally shoot the Lee 160 TL-312 unsized over 16 grains of Alliant 2400 in our monthly 100 yard reduced CMP matches out of my M1903A3 two groove. I usually score 250-260 (A-Course). Big issue on the low scoring is the offhand and not hitting the target. Lately my 100 yard prone scores which usually averaged 98-3X had dropped to the high 80's low 90's. Rapid had gone from high 80's low 90's to low 80's. Just to rule out the bullet, I went yesterday with the Ed Harris "The Load" using Promo instead of Red Dot and pulled M-80 147 grain fmj (apples, oranges and pomegranates, I know). Well 93-1X, 84-0X, 66-0X (fussed over the last shot and dropped it out the bottom, par for the course). Well seeing the the amount of variables was of no real consequence, I have determined that boy I wish I had my 20 year old eyes back (I'd take the 20 year old body too, but that might be asking a lot). They say seeing is believing (well at least half of what you see...) and a crisp front sight well centered makes a big difference, as does a solid hold. Amazingly, my sight dope was exactly the same as with the cast bullet.

Happy Thanksgiving and stay safe.

Dave

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Shopdog posted this 2 weeks ago

One thing you can try is instead of a "straight" taper,either make or buy a "bridge" reamer. Some leades, and some tapers just don't jive. Going with a radiused reamer,especially spiral ground (bridge),can sometimes have a dramatic effect. I use each,tapered and radiused mainly on nose sizing dies on the section just before,the first drive band.

While I understand Pope's reluctance to mess with "sizing",in the conventional sense..... where it's a push through design. You aren't changing any out of balance,you're simply pushing it somewhere else. Think instead how centerless grinding works vs swaging. No,am not suggesting you "grind" bullets. It's the direction of the inputs..... tough to describe.

Very hard posting on this site. Last post I made was a jumbled mess of things. If this one does the same,apologies. Not a problem on other forums. And can't post pics here either.

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