If you shoot at 50yds to sight your scope in and try grouping some reloads can you get a good idea of what the groups will be like farther out? I was out shooting today and the wind was really going good. I did not go to 100yds I just stayed at 50. This is only the 2nd gun I have tried to reload for so Im still trying to learn. I know I need to shoot groups at different yds to really see what they do but Im just trying to get something good at a 100 first. The gun is a Mossberg 243.
It doesn't always work that way. You will run into loads that seem to be so-so at 100yds and then tighten up farther out (MOA wise). In my experience it seems to happen with long boattails. In my AR with a 24" barrel a 55gr flat base bullet would group just as well as a 69gr SMK. But beyond that the 69gr seemed to get down to business. Some of it is due to the SMK flying better but there is also the bullet trying to stabilize itself. It also seems this becomes a bigger problem as you get into the larger calibers. The .50BMG shooters do not shoot 100yd groups, they feel the bullet does not fully stabilize till about 300yds (they call it going to sleep). What you run into is how stable the bullet exits the barrel.
The Marines always believed accuracy should be tested at 300yds and the newer 7.62 sniper ammo is tested at 300 and 600yds.
The tricky stuff is best left to those who are highly experienced in operating at the ragged edge of stability and sanity.
I don't know how much you gleaned from that but unless you are fairly well versed in exterior ballistics probably not much. There is a lot that goes into truly understanding a spin stabilized object in flight.
Bottom line up front, yes and no but mostly no: if your loads are shooting into two inch groups at 50yds they are only going to be bigger as range increases or just because you are shooting a ragged hole at 50yds does not mean that your gun will hold .5MOA at every yardage. I have one gun that will shoot .4MOA at 100yds with boring regularity but at 300yds it is a solid 1MOA gun. I have others that will hold under .5MOA to the furthest range I have shot them if I do my part to deal with the wind. I don't personally own or have ever shot a rifle that shoots 1MOA at 100yds and .3MOA at 500yds. I had a conversation with Kenny Jarrett about 15yrs ago where he told me he had just built a gun that shot 1" groups at 100yds and would produce 1" groups at 600yds. I'm not saying it can't happen but I've never owned a laser gun.
My suggestion for loading any rifle is to load ladders and shoot them as far as your range supports (I start at 300yds but if 100yds is all you have it's all you have) and if the wind is howling and you can't correct for it wait for another range day (eventually you need to shoot in the wind as it is the most difficult aspect of mastering rifle shooting). Ladders are hands down the most efficient way to develop loads I have ever used. It gets you into a velocity band that will allow you to maximize harmonics and if it is a balanced load will have minimal velocity spreads which become increasingly important as range increases.
I start with the bullets jammed .010" into the rifling and load from a book min to max plus in .5gr increments until I hit a load that is showing pressure signs and call that my max for MY GUN. All rounds are shot at the same target with no adjustments and eventually form a node. I then take the charges that formed the node and load in .2gr increments between those charges and back up 100yds shooting all rounds at the target with no sight adjustments from first to last shots. In a session or two you will have one or two charges nailed down. I then load a five shot group of each and fire them for group and velocity. Whichever shoots better gets tested again with seating depth changes in .010"-.020" increments depending on bullet type. You can test the final charge by adjusting .1gr either way, smaller seating depth changes, or testing a different primer. It is systematic and efficient. Google Audette Ladder if you need more info.
Post by sourdough44 on Sept 25, 2013 9:48:02 GMT -5
FYI, if one loads long to where the bullets are jammed into the rifling, you risk getting a bullet stuck in the bore while unloading. Not the end of the world at the range, can be a real pain out hunting.
Correct. I only start jammed because you can more safely determine a "do not exceed" load in your rifle with bullets jammed. Once you drop down below that load and come off the rifling you will not ever exceed those pressures generated by jammed bullets and your "do not exceed" load. If you start out at SAAMI max length and load until you see pressure and then play with seating depth if you go longer you have no idea what pressures will jump to without tracing. That is why I started jammed and work backward.
Thanks for the replies. So how do you tell if the bullet is in the lands or not? I think I know what your talking about but not sure. For my 30-06 I can take a shot case and put a bullet in the mouth before sizing and cycle it and it pushes my bullet back into the case. That is what I measure and go from there on that rifle. But my 243 will not do that with the 58gr bullet I was trying to use.
Your method will work fine. Whatever length you get using that fired case and bullet I would ad .010-.020" to go from kissing to jammed and account for dimensional variations between bullets (even in the same box). I don't doubt that a 58gr bullet didn't reach the lands of your .243Win.
Last Edit: Sept 27, 2013 5:59:38 GMT -5 by 7mmfreak: add info