CUP formula

English Mike · Posted: Sat Aug 02, 2008 12:53 pm Post subject: Re: CUP formula

Interestingly, Lyman lists their STARTING load for the 85gr HPBT using H4831 as having the greatest potential for accuracy & that's 5.5gr below the max. load.

Start load:
41gr
2832fps
36,400CUP

Max. load:
46.5gr
3266fps
49,600CUP

Oddly enough, when using the same powder but a 90gr FMJBT it's the max. load that is rated as having the best accuracy potential.

Fascinating stuff.

phill21 · Posted: Sat Aug 02, 2008 1:37 pm Post subject: Re: CUP formula

Welcome Dmickey, good to see you stepped right to the plate mate Smile

nothing wrong with loading for accuracy, i am just traveling down the same dirt track as most reloaders when they have not been reloading long.

Although i do get to pick the brains of some mighty smart people along the way Very Happy

You know looking at the time some of these posts where done i see a few non sleepers HMMM Bushy> Razz

phil

Bushmaster · Posted: Sat Aug 02, 2008 2:28 pm Post subject: Re: CUP formula

I hate to be the one to tell you Phil, but it is only 1630 here and I don't go to bed until 2400...I'm up at 0700 to feed horses...

chambered221 · Posted: Sat Aug 02, 2008 3:28 pm Post subject: Re: CUP formula

Bushmaster wrote:

I don't go to bed until 2400...

Don't you mean 0000 hrs. ???? Laughing

Bushmaster · Posted: Sat Aug 02, 2008 8:12 pm Post subject: Re: CUP formula

Naw...2400...I like to go to bed on the same day I woke up... Laughing

Vince · Posted: Sun Aug 03, 2008 2:00 am Post subject: Re: CUP formula

As a few of the guys have said welcome to HuntingNut dmickey. Bushy's already noted you have a beer and have grabbed a stump mate...grab another beer and feel free to join us at the fire.

Good to see you are happy to have a say...that's the best thing about "The Nut", everybody is free to have their say and offer the benefit of their knowledge and experience. It is a great help to those that are taking their first steps in the world of reloading.

Cheers, Vince

shrpshtrjoe · Posted: Sun Aug 03, 2008 4:39 am Post subject: Re: CUP formula

dmickey wrote:

What's wrong with loading for accuracy instead of velocity? I'm sure the game won't notice a slight decrease in velocity!

Welcome to the HuntingNut dmicky. I agree . Accuracy (imo) is more important than speed. Less pressure is easier on your equipment your barrel will last longer you get more reloads from your brass ect.. I have only had one rifle that shot better at max loads a Win mod 70, 264 Win Mag. If I need to push a cartridge to the limits to get the performance I need then I will use another cartridge for the particular task. Very Happy

Joe

Bushmaster · Posted: Sun Aug 03, 2008 10:21 am Post subject: Re: CUP formula

I guess a "one time poster"...[sign] Sad

phill21 · Posted: Sun Aug 03, 2008 5:39 pm Post subject: Re: CUP formula

Bushmaster wrote:

I hate to be the one to tell you Phil, but it is only 1630 here and I don't go to bed until 2400...I'm up at 0700 to feed horses...

AAAH!! I knew that Embarassed

Using winchester brass, winchester 9 1/2 primers WIN 760 powder 85gr Seirra HPBT with an OAL of 2.585"

Its not raining Very Happy

so grabed my guns and bye dear, ran couple of foulers thru sigted my rifle for 200mts and tryed the load not bad 1.3" @ 200 so sighted her in for this round grabbed the young (37) and went out to the mates farm spotlighting.
Lost count of the roo's we shot but got some realy nice skins and the 85 HPBT out to 400 sure makes mess of the roo's.
Took a rabbit @ 100mts the 85 HPBT turned him inside out and 1/2 skinned him wish it was a tracer it could have cooked for me too> Very Happy

Cheers phil

ElyBoy · Posted: Sun Aug 03, 2008 7:17 pm Post subject: Re: CUP formula

Sounds like you are having WAY too much fun Phill.

I have to wait a month yet to kill anything. Crying or Very sad

Glad to see that you are getting good accuracy.

1.3" Groups at 200 yards isn't nothing to sneeze at. That is one fine group with any load.

Eric

btefft · Posted: Sun Aug 31, 2008 2:25 pm Post subject: Re: CUP formula

There is no reliable formula for CUP and FPS. Don't waste your time.

Besides, I stay in the mid ranges of reloading and only look to compare pressures of one recipe versus another.

For example, I see in the Lyman 49 Manual (p310) that
IMR-3031 - 47.2 grs - 1621 fps - 19.800 CUP
AA-2015 -- 44.5 grs - 1585 fps - 21,100 CUP

What strikes me is that AA uses less powder, develops slower fps, yet produces a HIGHER CUP.

For that reason, I would use IMR-3031.

Hack

hunterjoe21 · Posted: Thu Sep 04, 2008 8:07 pm Post subject: Re: CUP formula

I too was obsessed with velocity when I first started loading ammo. Didn't take long to realize that "Faster aint always better" as Grandpops used to say....

As a friend at the gun club says...

"You can't KILL it if you can't HIT it"........