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Joined: May 2003
Posts: 53
Campfire Greenhorn
OP Offline
Campfire Greenhorn
Joined: May 2003
Posts: 53
Hi Ken, first off,Thank you for the excellent & outstanding (Bible) of yours, signed copy # 827, on 02/18/00, has proved a life saver several times for me.
You probably don't remember my case you helped me with.
224 Hansell L.R.V.T.(a 30/06 case with DOUBLE Necks and Shoulders, down to .224 Cal, 60.0 grs case cap, length of 2.420").

Have been shooting and building loads for it the last 2 yrs(one small carefull step at a time, working in Very uncharted waters with THIS case design,) 60 to 75 gr bullets only, want the highest BC for long range hunting and varmint thumping,along with the lowest pressure possible at the highest speed (safely) and still keep moa out to 1000 yds( if possible), so far there has not been any major problems to 500-600 yds (if I do MY part correctely, except with certain bullets).

I have finally found some Retumbo,Win WXR,MRP powders, but can't find the relative burning rates for the above listed fuels, so I can use my QL program, have any suggestions/Ideas.

Have used the following powders,4831,Win 760,N 160(have the fast lot),H100,7828,RL22(best so far). Want 90-100% case cap with the lowest pressure(50,000 psi and highest vel (average 3200-3400fps, w/75gr in 26" ss Shilen AG bbl).
I have a minor problem with this bbl, 60-75gr bullets from Hornaday/Speer/Nosler/Win shoots ok, Sierra bullets BLOW up every time,regardless the weight, same load with all the same bullet wts of 60grs, 46.0-RL 22, vel at 3200-3300fps(chrono), Any? reasons come to mind, why does this only happens to the Green ones.(need some help).

I think I am missing something with the green ones, but can't find out where?

Would greatly appreicate any or all advise or help on getting the BEST ballistics from this case design, and then the same case design will be tried using the 270WSM case with the same angles on shoulders and SAME case cap. and then the reamers will be improved with 35 degree angles, and the same info learned from original case tests will be shot thru the same bbls(rechambered to new case design).

ps, excuse the mistakes, first time doing this, getting on line, (attemping to run this &%#*^%$ machine (self teaching) with all the computer tech talk/words, had it just over a yr now, and it's still got a choke hold on me, but I am NOT giving up yet.
"When the going gets tough, the tough get going, Only the weak, bitch, gripe and die.(173rd ABN 2/503 VN 67-68)."
Thank you,NVRELOADER.


"When the going gets tough,
The tough get going,
Only the weak,bitch,gripe and die"
173rd ABN,2/503 "Recon" VN 67-68
GB1

Joined: Dec 2000
Posts: 29,348
Campfire Ranger
Offline
Campfire Ranger
Joined: Dec 2000
Posts: 29,348
Forget the load for now and look at only two things -- (a) the fact that bullets are blowing-up and (b) the relatively low velocities for this to occur.

From these two facts, it seems obvious that your barrel is spinning those bullets too fast at velocities that seem too low for this to occur. In tests, for example, the Hornady 75-grain .224 A-Max was most accurate at about 292,000 rev/min and began coming apart at about 330,000 rev/min.

At 3,200 ft/sec,
� a 6-inch twist spins the bullet 384,000 rev/min. Too fast.
� a 7-inch twist spins the bullet 329,100 rev/min. Marginal at best. Most likely too fast for some bullets.
� an 8-inch twist spins the bullet 288,000 rev/min. Should be no problem with a good bore.
� a 9-inch twist spins the bullet 256,000 rev/min. Should be no prolem with a good bore.


At 3,300 ft/sec,
� a 6-inch twist spins the bullet 396,000 rev/min. Too fast.
� a 7-inch twist spins the bullet 339,400 rev/min. Too fast.
� an 8-inch twist spins the bullet 297,000 rev/min. Marginal
� a 9-inch twist spins the bullet 264,000 rev/min. Should be no problem.

The first probable culprit is the twist -- probably too fast.

Another probability is the surface of the bore -- probably scoring the jackets excessively.

Also possible is that the number of lands -- in conjunction with the above -- is just too many. The fewer the better.

And it may be also that the one brand of bullets has thinner, weaker jackets.

My latest .220 Howell rifle -- with my cartridge not greatly different from your cartridge -- can drive the 75-grain Hornady A-Max out the front door at 3,600 ft/sec (at moderate pressure) from its 9-inch twist (288,000 rev/min). This barrel has three grooves and has been lapped very smooth with a consistent diameter from chamber mouth to muzzle.

Your rifle is almost certainly spinning your bullets faster (shorter twist) and scoring their jackets more heavily. That's my best guess, based on what you've posted.


"Good enough" isn't.

Always take your responsibilities seriously but never yourself.



















Joined: May 2003
Posts: 53
Campfire Greenhorn
OP Offline
Campfire Greenhorn
Joined: May 2003
Posts: 53
MR. Howell,
Thank for the reply,
maybe I should have expressed myself more clearly,

ALL bullets tried so far in the 60 to 75gr range shoot (read accurately) from this bbl.

EXCEPT the green ones, 60,69gr HPmatch,only 2 tried so far,I want to try the 77 & 80 gr wts, but can't force myself to spend the $$$, if the 60-69 bullets will not perform.

At this time I have stopped trying them and shoot all the rest, The 75gr Hornaday's are the best so far.

Could fire lapping(very lightly) maybe? solve the problem with the green ones?

Have you or anyone else on your forum tried this fire lapping?
I have grave concerns???? about running lapping grit thru this bbl at this time.
Has anyone else run into this problem, one brand of bullets BLOWING UP and all others shoot moa or better(using same load,cases) just changing bullet brands.

ps, I forgot to add, Please advise the total cost of your new book #2 to your first book, and I'll have a MO for the total amount on the first Pony express headin your way.
I would love to have the same # 827 same as my first signed copy,
Thanks again.
nvreloader.


"When the going gets tough,
The tough get going,
Only the weak,bitch,gripe and die"
173rd ABN,2/503 "Recon" VN 67-68

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