Group size the same at 100 200 300 yards. What gives?Posted by TorontoAlex on March 30, 2015 at 12:47 am
I broke in my .270 t3 laminate this weekend and I really like the gun. I reloaded my first box of ammo which were 130gr hornady sst with 55gr of H4381. I didn't expect much in groups and I am getting over 1 moa groups. I do realize that I must fine tune the load so not too worried. One thing I did notice was that my groups appeared similar at 200 and 300 yards! This is waiting 5-10 minutes between 3 or 5 shot groups. Any explanation for this?
MemberMarch 30, 2015 at 2:10 am105 Bullseyes
Post some target photos so we can see what you are describing…are you saying you groups are the same at 100 / 200 / 300 in size?
MemberMarch 30, 2015 at 1:15 pm1 Bullseye
Yes my groups are about 2 inches wide at 100, 200 and 300 yards. Is this common or do I just need to practice more? I don't have pictures sorry.
MemberMarch 30, 2015 at 1:44 pm105 Bullseyes
The good news is its a 2″ group at 300…Bad news its a 2″ group at 100
I've never seen a situation where a gun will hold the same “group” size from 3 different yardages like this. Normally if your groups are 2″ at 300, they would be 1″ or less at 100 for sure.
Without target pictures showing the groups there isn't much I can help with. It seems like an odd situation.
MemberMarch 30, 2015 at 5:39 pm1 Bullseye
Ok thanks. My guess is I just need to practice more.
MemberMarch 31, 2015 at 9:57 am1 Bullseye
Possibly the bullet is not stabilising until its gone past 100 yards
MemberMarch 31, 2015 at 7:01 pm105 Bullseyes
Its possible it doesn't stabilize till after 100yrds, but you would think the group would be still be smaller at 100 or open up at 300…Theres even a 8-9″ drop in elevation at 300 if zeroed at 100,…so theres a lot happening between 100-300yrds with that load.
I don't think we have all correct data needed…if we had group pictures at 100 and 300 for exact measurements and to see how the bullet is impacting the target it would make it easier to determine what's going on…
Is it possible your groups are 1.5″ at 100 and say 2.5″ at 300? Are you measuring everything perfectly,
Or just eyeing it and guessing? A triangular group pattern is deceiving sometimes if not measured on all 3 sides.
MemberApril 3, 2015 at 4:47 am21 Bullseyes
Interesting observation. Brian Litz of Berger fame has been working on a project that directly relates to your experience. He heard some anecdotes of rifle-bullet combos that seemed to shoot smaller moa groups at longer distances than they did at 100 yds, (eg. 1 moa @ 100 yds and 1/2 moa at 300 yds). He has not observed this phenomena with his test set up, which consisted of a thin paper target at 100 yds and another target at longer range (300 or so yds). With the rifle sighted to hit both targets with the same shot (using an offset aiming point, ) he recorded group size etc on both targets. He hasn't oberved any occasion where the closer group, measured in terms of moa, was larger than the simultaneous further group. Interestingly, several shooters came to his range to to recreate the scenario and shot noticeably smaller groups at 100 yds while aiming at the 300 yd target than they could achieve while aiming at the 100 yd target. This suggests to me that something was going on with shooter psychology or physiology rather than a physics mystery.
You might try setting up a target at 100 yds, and an aim point at 300 with the rifle sighted to hit the 100 yd target, to see if the the groups you get at 100yds jive with the moa you saw earlier.
Thanks for a very interesting observation, and good shooting!
MemberApril 8, 2015 at 4:43 pm1 Bullseye
Sorry for the late reply.
I was not measuring anything, just eyeballing. It could very well be shooter psychology. I am much more focused shooting 300 yards than 100. I just enjoy it more so put more effort into it, now that I think of it.
My buddy told me the bullet may not stabilize till 300 but like someone mentioned it makes no sense for a bullet to shoot tighter groups further away.
I have noticed the recoil lug is pretty messed up and that pisses me right off. So I'll replace that I guess and see what happens. Then load development.
MemberApril 11, 2015 at 3:10 am1 Bullseye
Alex, you might find it interesting to follow my own post as I have been trying to get consistent sub-MOA performance from my new Tikka T3 Lite SS in .308. You can read about my discoveries along my own journey here: https://tikkashooters.com/public_html/general-discussion/hunting-the-sub-in-'sub-moa'/msg3517/#msg3517
That said, I may have had an epiphany, today, that may offer a possible contributing factor to explain your counter-intuitive observations. You never mentioned what kind of scope/reticle/magnification/target, etc. that you were using. But as I have finally gotten consistently into the Sub-MOA Club at 100 yds over my last few range trips, I have begun to notice that my groups shot at 8X are at least as good if not better than my groups at 15X. Intuition tells me that I should expect to get a more precise hold with higher magnification (just as you would expect larger groups at greater distances, everything else being equal). But my range data, too, is (just slightly) contrary to my intuition.
My scope is a Weaver Tactical 3-15x50mm. It has a FFP mil-dot reticle with mil adjustments. Nice scope! I eventually intend to stretch this rifle to longer distances, so I intend to tinker with doing range estimation with my mil-dot reticle, at some point. The FFP reticle is ideal for that. That is what makes this a good “Tactical” scope. But the FFP reticle looks kinda fat at 15X. It really makes it more difficult–not easier–to judge a precise hold (i.e. sight picture) shot after shot. That's why target shooters are perfectly happy with (cheaper) SFP reticles. So what I am suggesting is that, depending on your scope (and equally important, the style of target you are aiming at), you may be getting a more precise hold as you shoot farther and farther, thus compensating for the increased distance. It's a hypothesis, anyway!
MemberApril 19, 2015 at 5:29 am21 Bullseyes
Nice scope birddog! Do you have any advice for using a lower power scope?
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