Riddle me this Riddle me That

BigBlack · Posted: Mon Oct 20, 2008 8:36 am Post subject: Riddle me this Riddle me That

Okay new reloader still learning as much as possible. I have been working on my 243 loads and am getting MOA groups at 100 yards pretty consistently now. Preparing it for hunting I fine tuned the scope adjustments and then popped off a few groups at 200 yards. Surprisingly my groups were only about 1.25" to 1.5" consistently. So at 100 yards I am about 1 MOA consistently then at 200 yards .6 to .7 MOA, why not closer to 2 MOA. I was under the impression (remember new reloader here) that if my group size was 1" at 100 yards I could expect 2" at 200 yards and 3" at 300 yards and so on.

Wind was relatively nonexistent this trip.

Not looking for flames only instruction or enlightenment.

Thanks
BB

Bushmaster · Posted: Mon Oct 20, 2008 9:32 am Post subject: Re: Riddle me this Riddle me That

What rcmodel said...

roklok · Posted: Mon Oct 20, 2008 9:34 am Post subject: Re: Riddle me this Riddle me That

There could be many variables at work here. Were you using the same size and style of target at 200 yards as 100 yards? If so,it could be that the smaller appearing target at 200 yards is causing you to concentrate more or do a better job of centering your reticle which leads to greater consistency. Is your scope an adjustable or fixed parallax? If it is fixed, it may be set for closer 200 yards than 100 yards. This also would contribute to greater consistency. I have read some pretty knowledgeable shooters claim that the phenomenom you are describing is possible because the bullet is more stabilized at longer ranges but I am not convinced of this theory.

Dawgdad

Your expectation is the general rule but it is not etched in stone. Other times a 1 moa group at 100 is 6 moa at 300 .

Let me add here I have seen loads that has groups that fall apart at distance but I have not seen ones that shot poorly( more than 1 moa) at close range that shoot well(1 moa or better) out 300-600 yards. If you ever watch someone else shoot through a spotting scope you can see the "vapor trail" of the bullet as it flys down range. I watched a friend try to shoot 55 FMJ .223's at 300 yards. The track was straight as a string through the first 200 yards or so but the last 75 yards to the target they would start to corkscrew a bit. It really screwed up his scores but taught us a good lesson. Use a heavy stable bullet for 300-600 yard target shooting! 75-80grainers just fly straight as a string all of the way out there. The results on target in reduced group size was significant too.

Usually the "boat tail effect" of a more stable at longer ranges bullet occurs at ranges beyond 200 yards. Many match shooters use flat base bullets for reduced range matches of 100-200 yards with good results.

Are you shooting boat tail or flat base bullets? What is your load? Velocity? It may be that all of the load development and testing has made you a better shooter. Did you shoot the 100 and 200 yard groups on the same day from the same lot of loads? Clean barrel? dirty barrel? You mention you are new at reloading, perhaps your technique is improving too. That is a good problem to have.

Pumpkinslinger

I've read that it can take a bit for a bullet to stabilize after it leaves the muzzle. Maybe that’s causing your situation.

SwampFox · Posted: Mon Oct 20, 2008 1:20 pm Post subject: Re: Riddle me this Riddle me That

Sounds a lot like you were shooting a 6mm boat tail bullet.

If so this applies; The boat tail bullet will most times not be fully stable at 100 and can require a touch more distance to get its act together. The BT bullet was designed for long distance. From 125 to zero yards you are normaly better off, group wise, to shoot a flat base bullet as the FB is stable out of the muzzle.

For best results you should select your bullet configuration based on the average distance you will be hunting with that bullet. Open fields, the BT, woods, the FB.
Best,
Ed