Thread: Accuracy troubleshooting suggestions?

Good Day,

Kimber Montana .308, 18” w/DPT suppressor shooting Hornady SST 165 gr., 2700 fps, 200m zero (per sight in at 100m range at 2.8 inches high).

Was shooting at a target recently and was about 19 inches low at 350m, decent 5 inch group (shooting off of crossed tramping poles and my day pack under the rear arm). Did not try dialing to correct, but 19 inches low (or 3.9 moa) was correct according to my ballistics app (shooters calculator.com).

I then added a DPT muzzle brake (replaces end cap), a stainless blast baffle, and one more alloy baffle. Recoil is massively reduced, can pretty much stay on target after shooting even at 15x.

Last night I’m out on the hill, stalking in on a mob of 4 yearlings across a gully, when one spots me. I sat down in the tussock and ranged it at 335m, and figured it was a good opportunity to try a longer shot (almost always stalk to within 200m). Dialled 3.8 moa. Clean miss (son thought it may have been low but wasn’t sure). Two more shots before it ran off, both misses. Again, son thought they were low.

Should I re-chrono? Did I miscalculate moa? Would the two extra baffles and muzzle brake change (reduce) muzzle velocity very much? They didn’t significantly change point of impact at 100m, maybe 3/4 of an inch higher, but I haven’t tried shooting at distance (hard to get access to the farm with the 350m target).

Any other suggestions?

Thanks!

I wouldn't read too much into it if it was a 350m sitting shot.

You’ve changed your POI, which only magnifies the further out you get.

Re-zero your scope for the modified setup.

Zero needs to be checked after any change made.

Had a similar event happen to me, fortunately a mate was trying out his flash harry spotting scope and phone adapter so got it all on camera. Short version is that I was missing high by some margin.

I eventually came to the conclusion that I was shooting high due to not having a rear support. (I was crouched behind a bank) I have since shot at a target at a similar distance and all six shots would have taken the deer.

The lesson I learned that day is that if I wish to execute a shot at distance I need to be prone with something supporting the rear of my rifle.

Reduction in felt recoil can lower the point of impact by reducing muzzle flip - could be a large part of a 'miss low' at longer range. Need to recheck zero with the new muzzle attachment to know though. As someone noted, any change means a recheck.

Zero needs to be checked after you've made a change. Yes, extra baffles/muzzle brake can make a difference. Doesn't matter what ballistic app you've got, until you verify at known ranges they are only an educated fucking guess. Check zero at an accurately measured range.Better yet go along to a NZDA or NRA range and check zero and drops at verified ranges. Verify against app and modify app inputs until you get app outputs that coincide with actual results .Do tall target tests or whatever to verify your scope adjusts correctly per click/MOA or Mil. Until you do this you're pissing into the wind. And don't forget operator error/capability. Also...practice,practice,practice. I generally shoot at least 24 rounds a week when not doing pest control and still make the odd fuck-up, we're all human and stuff-up from time to time.

My 308 Kimber is very sensitive to "hold" even with a braked can. I have resolved to practice more.

IMHO there’s nothing to even talk about until you’ve re-zeroed after the suppressor changes?

My 308 20 inch barrel zeroed for 200yds is 1.5inch high at a hundy using150ssts 2900f/s.Using Hornady 165gr ssts .Theres only .5 inch difference for 400yds zero.Actually the 150gr ssts have a bit more energy than the 165gr.
As the boys have said rezero.
Iv just got a slightly bigger suppresser fitted,so I had to rezero.Heres the result,get yr 100mtr zeroed good first,then stretch the legs.

4 shots in one hole,one flyer,2 clks right,job done.
Thats with a thermal clipon on front of scope

Thanks all, truly appreciated. Just to be clear, I did re-zero, but only at 100m, and was using a rear support (sand bag).

I will re-zero at 100m using my go-to field setup, which is two crossed tramping poles (I have some attachments called Quick Sticks that lock them together) and my shooting arm/elbow on the frame of my daypack, and then do as Woods says: tall target tests, verify drop, clicks, etc.

In the tussock hills where I hunt, I can’t always get to a rock, and shooting prone is never an option. My goal is to consistently shoot to 400m off the poles (80% of shots within an 8 inch circle). We shall see!

I reckon if you going to spend $150-$200 on a hunting trip each time,say once or twice month.Go to the range befor each trip or 2.Fire 2 or 3 rds =$12 or so.Just to make sure yr rifle n scope are in tune.

Greetings all,
I have heard this tale over and over again over the last 30 years or more. Rifle zeroed at 100 metres or there about and being out at longer ranges when dialled resulting in missed deer. Step 1 is if you want your rifle zeroed at 200 metres then shoot it at 200 metres. Next check it at 400 metres to make sure your trajectory matches your dial up values. Don't have a range? Find out where your nearest NRA range is and make contact. Also as mentioned use exactly the same set up for zeroing as you do in the field.
Regards Grandpamac.

bang on Grandpamac on TV many years ago a certain idiot ( wont give name may not still be with us ) who thought he could hunt and present a hunting show zeroed a 25-06 Remington on a track before going hunting - looked like about 100 yd range - showed us target - it was at least 1 1/2 high and 1 1/2 to left - announces on TV near enough I knew he was an idiot from some of the stuff he did on show but after that just completely wrote him off as a bloody moron

Fire 10 rds at the range per month.You'll only need 2 rds to shoot 2 deer per month,all going well.