With all the recent discussion about pressure....

11 September 2003, 04:45

T/C nimrod

I thought I'd share a perfect situation in regards to loading for a Contender - Project 41:

Here's my situation: I have a ramp of Blue Dot powder that went from 10.1 grains to 13.5 grains in .4 increments. (13.5 is one load below published max) Starting load of 10.1 grns. showed .0008" case expansion, zero primer appearance change, and low recoil (as compared to previous shooting sessions). The load of 13.5 grns. shows a slightly discolored primer (under a magnifying glass), slightly straightened primer edges, a .0015" case expansion, and noticeably more felt recoil (again in relation to the previous loads).
It was at this load that I printed the best 5 shot group @ 100 yards (as compared to the previously fired loads with the same components). By the best group I mean the smallest spread, 2nd lowest standard vertical deviation (.27"), lowest standard velocity deviation (9fps), and lowest velocity spread (12fps). Now, would you proceed or stop here?

There are some more details that I used to make my decision, but left them out for a reason - I'm curious how others would handle this?

By the way - this is what may get me removed from another board [Eek!]

11 September 2003, 05:09

6.5 Bandit

T/C nimrod,

I would stop there.. Reason being I think with the little flatness you are getting and the fact the case expansion has increased signifantly you are approching max.. you maybe fine to go higher but I would not want to risk it....

Ya looks liek we are both doomed on that site lol... He will prolly ban me after my last post might want to read it before its gone lol...

6.5 Bandit

11 September 2003, 05:59

T/C nimrod

Are you trying to start something with me? [Big Grin]

11 September 2003, 06:01

<NRC>

What was the environmental conditions of your test? (Altitude and temperature..)

I'd probably stop where you are, but depending on your answer to the above I might even reduce a bit.

11 September 2003, 06:20

6.5 Bandit

I would never do anything of the sort... lol [Eek!]

[ 09-10-2003, 21:21: Message edited by: 6.5 Bandit ]

11 September 2003, 06:39

T/C nimrod

quote:
What was the environmental conditions of your test? (Altitude and temperature..)

Good question(s). Altitude - don't have a clue, whatever the flatlands of Pennsylvania are.
Temperature - At the starting load (10.1 grns) ambient temp. was 58 degrees/ barrel at 69.3 degrees. At the last load (13.5 grns.), ambient was 67 degrees/ barrel was at 77.5 degrees. The first four loads gained 2 degrees after each round. The last three gained 2.5 degrees. This ambient temp rise took place over a 3.5 hour time period (9:00 - 12:30 am).

Added: there where 6 shots taken as warm-up and barrel fouling prior to load testing - that accounts for the temperature difference at the starting load between barrel and ambient.I load ten cases of whatever the starting load is and use them to "condition" myself and the barrel. They are also used to find point of impact on the target so adjustments can be made before the main course is served.

[ 09-10-2003, 21:44: Message edited by: T/C nimrod ]

11 September 2003, 10:24

<NRC>

If I'm not mistaken pressures would increase as the temp rises, and the altitude drops. You're probably in the green with your present altitude.

If you were to travel to south texas in july I'd probabyl start over and work up again just to make sure everything is still kosher...

Have fun.

11 September 2003, 10:30

cas

What are you gaining?

11 September 2003, 11:02

T/C nimrod

quote:
What are you gaining?

Cas - By this question do you mean what am I gaining by adding more powder?

11 September 2003, 12:18

cas

Yes.. what are you gaining by (a little) more velocity?

11 September 2003, 15:19

T/C nimrod

That's why I posted - I don't know what I have to gain. It would be nice if I could take a peek behind the black curtain, but it's all or nothing. I'm taking for granted your decision would be to stop as well. Interesting......... [Cool]

11 September 2003, 16:07

cas

Well.... all your really doing is making your gun wear out faster. What's "behind the black curtain" is a large piece of metal imbeded in your forehead, or a finger blown off.
Anything you shoot with it, paper of flesh, isn't going to care a wit if it was at 1350fps or 1480fps.

[ 09-11-2003, 07:08: Message edited by: cas ]

12 September 2003, 00:17

T/C nimrod

cas - I'm discussing, not arguing, and not diasagreeing with your ideas. I left out the velocities I achieved, wanted to see if anyone watched that data when working up a load. Hornady wants 1000 fps for proper expansion of their 210 grain HP/XTP - this powder is going to be cutting it very close at 100 yards.

Here's another tidbit: the 13.5 grain load printed 4 shots at .72" and the 5th opened the group to 1.07".

quote:
What's "behind the black curtain" is a large piece of metal imbeded in your forehead, or a finger blown off.

Gee, that's an incentive. [Eek!]

12 September 2003, 12:47

Paul H

The only time I've tried to hot rod the contender was with both a 10" 357 mag, and 10" 357 max barrel, to see what they could do. The problem with that approach is I didn't concentrate on developing an accurate load, and when I did find some loads that shot relatively well out of the barrels, they fell shy of my speed goals for the rounds. That was really silly, as the loads would have been fine for hunting.

Unless one is looking to see what a round can do, there is no reason to keep adding powder once you've found the sweet spot. Load up a couple boxes of ammo, and be happy that you have a good load. I've burned a good deal of powder, and sent alot of lead down range before reaching the aforementioned conclusion.