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Hi all,
Quick question. Is there a real difference between lesting .308 loads at 75 vs 100 yards? Only reason I ask is because I have a local (10 miles away) indoor range that is 75 yards and my closest 100 yard range is a 2 hour drive. I want to know if its absolutely necessary to test at 100 yards or if 75 will be adequate.
Thanks!
Usually if the SD are low, chances are your ammo is good. 75 yards is fine. Its all about what makes you confident in your gear.
Thanks for the quick reply!
I'd like to be 100% confident in my gear. If I need to go out to 100, I will. I just want to make sure I'm not wasting my time if I settle on testing at 75 yards.
If it groups at 75 and SD's look good (15 or under), I would be confident in the ammo.
OP, Do you have a chrono. I first consider what distance I will be shooting when I look at the distance I will be testing. No reason to test a rifles load at 300 if you will never shoot more than 75. I would test a target rifle at or near the distance I will be shooting in competition. Different bullets are designed to be more accurate at different distances. I have had great luck with flat base under 300yrds for instance.
Roger that. 75 yds will work. Especially if the 100 yd range is so far away. Down side to that is its better to have more trigger time at distance as opposed to short, but hey...2 hours to get 100 yard range?......man I feel sorry for you dude.
Thanks guys! And yeah, the 2 hour drive is aweful. Gotta love Illinois...
Cant you find a farm or something and stop to see if he would let you target shoot so you don't have to drive 2 hours.
I use 50 yards to test new loads. The difference in the point of impact from 50 yards to 100 yards probably isn’t more than 1/4 inch if that much. The difference between 75 yards and 100 yards would be less than that if any difference at all.
I dont have any farms near by. I'm only 20 minutes west of Chicago so my options are very limited. It'd probably be just as long of a drive to a farm far enough out with the available land.
You are not in Carrol Stream are you?
**** close. I'm in Schaumburg
If it helps any, I tried the Optimal Charge Weight (OCW) test at 50 yards. Mainly because my range had the 100 and 400 yard areas under renovations and I HAD to get some load tests in before a long range shooting opportunity.
It worked for me shooting out of a 26" BBL Remington 700 with 1:12 twist shooting 175gr SMK out of Lapua Brass and IMR-4064 powder. My rifle liked the 42.2gr of IMR-4064.. I started from 41.0 and worked up to 43.3gr. The sweat spot was between 41.9 - 42.5. however I will say this: the charge range worked well up to 500 yards, beyond that range I really needed to keep my charge tolerance tighter, within 1/10gr. My scope is Mil-Mil, so I started experiencing differences of +/- .4 Mils between shots beyond 600 yards (I loaded 42.2 (+/- .2gr) for the event).
Truth be told I was hitting 1100-yards with an OCW charge tested load at a 50-yard range so 75-yards should be just fine if you do your part.
Awesome! Thanks for all the input, guys. Much appreciated as always.
If you're going to drive 2 hours why don't you drive north to Winnequah gun club? Has up to a 1200 yard range
Obviously, the shorter the range, the smaller the groups. Since you're trying to sort the fly s**t from the pepper, you need to study the data carefully so that you know what it means. Remember, you're talking about tests which involve tiny differences in where the bullet impacts once you are able to shoot better than, oh say, .5 MOA. To properly evaluate the performance of your rifle/ammo combination, you MUST make careful measurements. If you're using a coin or a carpenters tape when you talk about group size, you're wasting your time.
For a few bucks you can get a computer measuring program, assuming you have access to a scanner. You can also use a cell phone to photograph your targets. I like On Target because it's cheap ($12) and easy to use. Scan your 75 yard targets, very carefully mark your bullet holes with your mouse, and the program will calculate all sorts of important data including Mean Radius with is a real PITA to do by hand.
By examining this information, you can make informed decisions about bullets, loads, seating depth, etc. As you no doubt know, accuracy and precision involve the sum of a lot of little factors and if you get most of them right, you can shoot small groups reliably. But to find which factors are working for you and which are working against you, it is critical that you collect meaningful data. That means making good measurements, especially when shooting at short ranges.