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How do I work up a load?
Posted: Sun Mar 04, 2012 9:35 am
by Watcher
I have got the kit now so how do I start my journey to the perfect load?
I understand the bit about getting to a safe load i.e. start at 10% below the maximum safe load and work up until signs of over pressure appear. What increments would you use?
What is the best way to get to the most accurate load? A pal has a chronograph so should I be looking for the load that produces the most consistent velocity? Or should I just get on the range and work for the tightest group; if yes then at what range? 100 yards seems the most sensible.
Sorry for lots of Qs!
TIA
Watcher (Matthew)
Re: How do I work up a load?
Posted: Sun Mar 04, 2012 10:12 am
by dromia
For rifle loads 1/2 grain increments work for me. Pistol type rounds 1/4 grain increments or less depending on how small the load is
If shooting at 100 yrds (minimum distance really) then I shoot 5 shot groups for starters and as a refine it I will the shoot 15 or 20 shot groups.
If you have access to 300yrds or more then the ladder method is good and less ammunition hungry.
A chrono is useful but not absolutely essential, as well as giving you the velocity which can help with letting you know when you are getting near high pressure, it will also show you extreme velocity spread/standard deviation which will show how consistent your ammunition is. However that will not always translate into the most accurate load only your target will tell you that from groups shot with as high a sample of rounds as you can load and shoot.
It is also a function of how many rounds you want to take out of your barrel life with load development.
Re: How do I work up a load?
Posted: Sun Mar 04, 2012 10:16 am
by Watcher
dromia wrote:
If you have access to 300yrds or more then the ladder method is good and less ammunition hungry.
What's that Dromia? Actually its much harder for me to get access to a 100 yard range than to either a 300 or 600 one.
Re: How do I work up a load?
Posted: Sun Mar 04, 2012 10:22 am
by dromia
Basically the ladder method is where you shoot one round of each load, as the velocity increases the POI climbs up the target, as you get near the sweet load for you rifle the bullet holes will get closer together on the "ladder" and then start opening out. That gives you the load spread that your rifle likes perhaps 3 or 4 shots 1 1/2 to 2 grain apart so that you can then refine the load within those parameters. There may be more than one sweet spot on your "ladder as well.
Do a search of the netty, I used to have link to the gentleman that developed the theory but I lost it when my hard drives went last year.
Re: How do I work up a load?
Posted: Sun Mar 04, 2012 10:37 am
by Watcher
Dromia,
Found this which looks the thing; I'll give it some study:
http://www.6mmbr.com/laddertest.html
Thanks
M
Re: How do I work up a load?
Posted: Sun Mar 04, 2012 10:46 am
by ovenpaa
I used ladder testing to prove loads on my 7mm and more recently the 6,5-284, the test gave very quick results, for the 7mm it was a change of bullet and ten shots proved the load.
The 7mm was interesting in that the fall of shot climbed high right as opposed to vertically and what i would say is try and shoot it at 400m+ and have someone at the other end to drop the target and mark each shot by number so you can go back and look in detail at your results. I used plain white paper with a visible aiming point and removed the whole sheet and took it home so I could make an informed decision.