Long COL loading

15 January 2002, 04:16

<bigcountry>

Long COL loading

Let me throw this theory out there. I recently got some good results loading my 300RUM. This load was difficult for me and I have only been loading rifle for about a year so I am still learning. This time instead of loading 3.64", I stay around 3.597" COL. My results are as follows with CCI Mag Primer, 180g Nosler PT and H1000 Powder.

92g 1.1" group
93g 1.0" group
94g 0.4" group
95g 0.9" group
96g 1.0" group

Now, most all reports I have seen on the net have showed max or a little over max load being the best groups. But I found to be in the middle of the range. Do you think people got good results a little over max cause they load thier COL 0.05" or
so over Max COL and they need more powder to accomidate the space they freed in the case?

15 January 2002, 04:57

Bigdaddytacp

quote:
Originally posted by bigcountry:
Let me throw this theory out there. I recently got some good results loading my 300RUM. This load was difficult for me and I have only been loading rifle for about a year so I am still learning. This time instead of loading 3.64", I stay around 3.597" COL. My results are as follows with CCI Mag Primer, 180g Nosler PT and H1000 Powder.
92g 1.1" group
93g 1.0" group
94g 0.4" group
95g 0.9" group
96g 1.0" group
Now, most all reports I have seen on the net have showed max or a little over max load being the best groups. But I found to be in the middle of the range. Do you think people got good results a little over max cause they load thier COL 0.05" or
so over Max COL and they need more powder to accomidate the space they freed in the case?
Bigcountry....If I understand you correctly you are loading and measuring the case and bullet length? the COL or cartridge overall length is ONLY important in the fact that the cartridge will fit in to a magizine and has little to actually do with accuracy...the length that matters is the distance of the ogive-contact point of the bullet with the rifling in the barrel-to the rifling....this changes with COL but as long as the case neck has enough bullet held to keep it straight and enough tension on the neck/bullet to allow good ignition/burning of the powder then COL doesn't really matter...it is the bullet jump,or lack of, that makes the load more/less accurate...extra powder space is a minor side effect of this difference..except in very hot loads and certain bullet types..Barnes X bullets for example...a tool -a comparator-is used to measure the ogive to base length for loaded rounds to find the prefered length of jump for the gun in question...Stoney Point,Sinclairs and others make these...good luck and good shooting!!!

15 January 2002, 06:24

<bigcountry>

I have the stoney point unit. I used to load right up to the rifling or .02" back from. I never had good results from that. I was explained from Sierra Rep. Rob that with heavy bench type barrels, the harmonics of a barrel doesn't matter and right up the rifling if where you want to be, but with sportster barrels, harmonics play an important role and a shorter COL or further away from the rifling might be needed to get the gun to shoot well, or match the harmonics of the barrel or you might have to adjust the load to match that COL and get dead ended by reaching the max recommended load. And thats the only way I have been able to get good results is to play with the seating. Just a peice of information that made sense for me.

15 January 2002, 08:53

LE270

quote:
Originally posted by bigcountry:
most all reports I have seen on the net have showed max or a little over max load being the best groups. But I found to be in the middle of the range.

Most loading manuals say that you usually get the best groups at a few grains under max. But each rifle and load is peculiar to itself, so you never know until you try.

16 January 2002, 09:22

<.>

quote:
Originally posted by LE270:
Most loading manuals say that you usually get the best groups at a few grains under max. But each rifle and load is peculiar to itself, so you never know until you try.

But "max" is an elusive concept. I'm finding that current load data is substantially below SAAMI spec. for "max" loads. So then what do you do? What about wildcat loads? I have a gun, bull barrel, .223 Ack. Imp. Rem. 700 PSS. What's the "max" on that gun? Why can't I just shoot whatever charge fits in the case? The 22-250 has the same exact bbl. and only a different chamber. Why can't I use 22-250 data as a load guide???

(I'm only half assed serious here. Don't get panties in a bunch about my blowing the gun and myself to bits.)

16 January 2002, 09:19

<bigcountry>

I do have my own max. This is a hunting gun so max for me is the max I can put in my mag or in the gun without detachable magazine. Call me crazy, but I like the extra bullets.

16 January 2002, 11:18

Atkinson

I have found that max loads are best with slow powders such as IMR and H 4831, RL-22 etc......the faster powders are less clear.

I like magazines and throats that match and bullets that are set way out...

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com