Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Hunting
Long Range Hunting & Shooting
Accuracy: Tale of Two New Model 70s
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="marksman1941" data-source="post: 3063684" data-attributes="member: 68542"><p>Take this with a gigantic grain of salt, as your mileage may vary. In a modern rifle, with a modern load book, loads are typically neutered substantially to the point that "max" is still well within safe realms. So for example, if a load book offers a range of 40-44gr of imr4064 under a 150gr bullet, starting at 40gr tends to be a massive waste of time and resources. In this case I'll typically start at 42.5-43.0gr or so and work up from there. </p><p></p><p>I've found that if a rifle is going to be picky with loads, it simply isn't worth fighting that load. Doing a ladder of 0.2gr and finding accuracy nodes is all fine and dandy if that node is 1.0gr wide, but if it's smaller than that then ambient temperature is going to change your group size beyond acceptable levels.</p><p></p><p>IMR 4064 is relatively temp stable, and changes about 0.5fps per degree F change. So if you do your load development at 60F, and hunting conditions vary 30 degrees either way, you have a 30fps spread of your average muzzle velocity. If your accuracy node is 0.2gr wide, and groups open up outside of that, odds are good temp variations will push you out of your accuracy node at some point.</p><p></p><p>Sorry for the rabbit hole here. This will likely go against some advice from others, it's just what I've experienced. Basically pick a bullet, test a small range of powder charges up near max and make sure groups don't deviate massively (or one charge tested in a variety of temperatures) and if it doesn't work move on to another bullet. Seating depth also plays into it, more so with some bullets than others, but that can be its own rabbit hole to chase.</p></blockquote><p></p>
[QUOTE="marksman1941, post: 3063684, member: 68542"] Take this with a gigantic grain of salt, as your mileage may vary. In a modern rifle, with a modern load book, loads are typically neutered substantially to the point that “max” is still well within safe realms. So for example, if a load book offers a range of 40-44gr of imr4064 under a 150gr bullet, starting at 40gr tends to be a massive waste of time and resources. In this case I’ll typically start at 42.5-43.0gr or so and work up from there. I’ve found that if a rifle is going to be picky with loads, it simply isn’t worth fighting that load. Doing a ladder of 0.2gr and finding accuracy nodes is all fine and dandy if that node is 1.0gr wide, but if it’s smaller than that then ambient temperature is going to change your group size beyond acceptable levels. IMR 4064 is relatively temp stable, and changes about 0.5fps per degree F change. So if you do your load development at 60F, and hunting conditions vary 30 degrees either way, you have a 30fps spread of your average muzzle velocity. If your accuracy node is 0.2gr wide, and groups open up outside of that, odds are good temp variations will push you out of your accuracy node at some point. Sorry for the rabbit hole here. This will likely go against some advice from others, it’s just what I’ve experienced. Basically pick a bullet, test a small range of powder charges up near max and make sure groups don’t deviate massively (or one charge tested in a variety of temperatures) and if it doesn’t work move on to another bullet. Seating depth also plays into it, more so with some bullets than others, but that can be its own rabbit hole to chase. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Hunting
Long Range Hunting & Shooting
Accuracy: Tale of Two New Model 70s
Top