Home Forums Hunting & Shooting Long Range Hunting 243 WSSM / 105gr A-Max / H-1000....First Visit!

Really. I was confident in the chrono readings. Consistently 3040'ish with the 45.6 gr load and dead nuts 3059 with the 45.9 load with an ES of 8!

I actually loaded 20 of the 45.9 load to check it out a little better. It shoots better.

3 in a hole literally at 100, 1 out. Got windage perfect at 50 first before moving out.

The only thing I can figure is that the bullet's BC out of my barrel is somehow changed. Had to reduce velocity in Ballistic by 300 fps ?!?

What's JBM tell you, in accordance with your confirmed drops? Or Shooter?

Sure seems like an input got out of whack somewhere.

Permit me to moderately hijack? It's pertinent

Ballistic uses JBM...

What about everything else, like sight height above bore, coreolis, zero range and height, LOS angle, etc? Those factors all add up as the range grows, as I'm sure you're aware. A down draft is always a possibility, as well, if the terrain has those sorts of features.

You said you confirmed zero before moving out, right?

A .307 G7 at 3105fps doesn't suck at LR, either. In fact it's almost like cheating. *grin*

Shot John Burns' rifle at 1200 and 800 in Wyoming...you're right....that thing will impress.

Do you think the 105 is inadeqautely stabilized? A foot more drop sounds like a lot..Does the 105 stabilize and shoot well in standard 243 10 twist barrels?

I was definitely thinking about the bullet's stability Bob.

Tanner,
Yep, Ballistic's computer is JBM

Jordan, everything seems to be input correctly.

Jesse, hijack away if you want!

Ballistic is calculating Miller stability at 1.14 for the A-Max out of my barrel

JBM says it needs to be at least 1.3 to 2.0

?

I have had similar problems with ballistic calculators. Just like you, I have weather station and have gone to extremes to input as much data as possible. I've measured scope axis above bore, etc. Many of the factors do little to the final solution.

I wanted to know how to fix the firing solution or what else to tweak? I am having trouble finding extended distance ranges to shoot beyond 300 but even at that distance my calculated solution will request 2.1 MOA come ups. In reality I need to add an additional 1MOA. Other rifles are very similar.

And all the programs do the same math...Sierra Infinity or free calculators from BigGameInfo. All are plus or minus .5"

Do I really need to fudge the fps 200-300 so it fits? If so, what shakes out at 600 if you get it tweaked at 300?

Or in reality the BC of used bullets are beyond inflated?

The first order of bidness,is to keep the horse in front of the cart...and to simply scratch things offa da list.

Speed,BC,ES/SD are known quantities(as quantified by the OP) and them are good things to have wrapped tidily. Such essentials,routinely meld in harmonious conjunction with numerous Boolistic Calculators and while there may be subtle deviations amongst the software ranks generated comeups,the differences ain't ever stark. Good info input,will reliably yield good comeups on the output.

The obvious that all are missing and are all too giddy about poking the pony behind the cart,is erector travel. To reliably arrange POA/POI intersection,you gotta deduce the flight characteristics of a given load,in a given atmosphere and have the means to RELIABLY alter it's course of flight,to intersect where the crosshairs are looking. To say the erector travel of the aforementioned 6-18x is suspect,is gross understatement. While easy enough to quantify,with but a single 100yd poke(so as to remove as much atmospheric from the equation as possible)...I'd be re-hitching the pony to the FRONT of the cart,prior to that easily discerned confirmation.

I'd haveta ascertain where the erector falls at the zero range and that in regards to the windage's relationship to it's mechanical center...if only for starters. It is undoubtedly cast hard to port or starboard and that will do no favors. Secondly,I'd wanna know where I was at in ele travel,regarding my zero and how much travel remains beyond that. Nailing both of them prudent points,is default money makers that'll bear copious fruit,lonngggggggg before loading(or firing) the first round for a new rifle. Hint.

Mounting systems is always suspect(both in their relative quality/integrity and their installation/torque),but I'll cast a gracious wand and go out on a limb and assume 'em to be in synch. Keep in mind that short receivers,closely spaced rings and long tubes(especially multi-segmented 1" versions)...are not a recipe for long term zero retaining satisfactions. Re-hint.

Now unto the crux and carts pulling ponies. You did not get a box of "soft" BC's. Nor did you get a transonic slip,in regards to the range(s) thus far cited. You did not get pinholes at 100 and keyholes at wayyyyyyy supersonic,due your twist rate...despite the hilarity of the chatter thus far associated,with such ruses. The odds on given,is that you've an erector which did not travel the full distance you input,regarding it's ele travel as the firing solution.

Soooooooo...cut to the [bleep] chase. Revisit the 100yd line,hang vertically stretched butcher paper and a nice little black dot at it's bottom. Then simply dope the erector travel for the solution that fell short and paste the crosshair on the single bottom dot. After that poke,simply measure the distance from aiming point to the boolit's hole and extrapolate the erector's travel as per that solution. Re-re-hint.

I know it'll take ALL the fun outta guessing and will allow you to cut to the [bleep] chase,but I've personally long had a warm/fuzzy for KNOWING and right outta da gate. Odd how them led to water,follow suit,after having seen the light. Do not be "suplized" that you find an erector soft spot,regarding it's ele travel...in a glass sighted hard to port or starboard. Nor be "suplized" that ele tracking changes,when nearing the end of the ele's cited travel. Further,understand that the full realm of ele travel is IMPOSSIBLE to realize,with an erector cast to port or starboard. Re-re-re-hint.

When you ain't dealing in KNOWN(proven on paper) quantities,regarding ele travel accuracy,ele range of travel and an ele erector's ability to track straight...then you is simply pizzing up many ropes and a guess is as good as you can ever do. Physics is a wonderful tool to bank upon and etched in [bleep] stone,which is why I find it curious that soooooooo many are in such a hurry to question it and long before the weakest link of ANY system and that being the erector proper.

You've been led to water. Re-re-re-re-hint.

Now as to dealing with an erector who's "click" graduation values as a single or in compilation,deviate from a cited design designator...who gives a [bleep]?!!? Simply denote the values and do bidness on the erector's adjustment,in correlation to the known values and POA/POI will reliably intersect. Rest assured,your stock don't give a schit,if the comeup solutions denoted on it's card...ain't harmonious with the graduation values slated by the Manufacturer. If/when encountering a flat spot in the travel(which is very typically at/near it's ceiling),simply denote when/where it falls and do bidness in those accords,if you are too cheap to skew the mounting system and ring the [bleep] bell.

Simply beat on schit and let it prove it's merit and weigh them findings as if they was gold...if only because they are. If/when sumptin' is suspect,focus upon keeping the pony in front of the cart and troubleshoot in that manner.

Pass the modest X's,shorter tube length,greater internal erector travel and hold the fluff.

With Miller stability, 1.4 to 2.0 is ideally stabilized, but 1.14 is still theoretically stable. Under 1.0 is unstable. Bullets become more stable as the distance stretches, so if you're seeing good results up close, then stability isn't the problem farther out.

EDIT: until you approach the trans-sonic range, at which point stability can become interrupted.

It helps to get a reasonably accurate drop model by getting a few reference points- POI at 100, 300, and 600 yards, for example.

Boxer's post is excellent. It's posts like that that make him an asset to the forums. IME, he's absolutely right. Of course, I assumed that Rick was using a proven optic, but something that I do with all my scopes before ever firing a round is to mount the scope properly, stress-free, using proper torque values, and then attach my Bushnell magnetic boresighter to the muzzle. The boresighter uses a grid with squares that measure 16MOA each, using a distance from the objective bell of about 22". This proves to be a mighty handy tool for testing reticle and erector values, travel, and usable elevation adjustment limits both with windage at mechanical center and with various amounts of windage dialed in.

Rick, have you been using more than one load in the rifle? If the AM load is the only load that isn't tracking properly with the software output, but other loads are matching up nicely with their respecive drop tables, then the optic isn't the issue.

Good post guys. I learned something today. Not to over simplify here but if the Amax were a little unstable in flight in the beginning wouldn't the BC be lowered? Would still have a good muzzle velocity but drop quickly there after. May be a stupid question but i have thick skin. Would it be worth shooting through the chrono at longer ranges to see what the speed is?

Just a little reverse redneck engineering mind at work.

Short-range results seem to indicate good stability.

Great post!

Thank you. Will re-read 3X more and put it to use hopefully Thursday for a shooting session.

Great information!

Yep Boxer, it's something I've thought about, but, as Jordan says, I shoot another load in the rifle that works perfectly for drop when inputting the correct velocity as taken from the chronograph. The scope's not the problem, unless it took a schitt after the last time I shot the proven load.

I shoot a 70 gr BT at 3725 fps and Ballistic's output is right on the money.

The bullet seems to be plenty stable as evidenced by nice holes even at long range.

The bottom line is that when I put 2725 in for velocity instead of the actual measured velocity of 3059, the drops match actual shooting. I've never had this problem to this extreme with any of the other profiles in Ballistic that I've set up (8). I forgot to note that when I shot the .264 WM, the dope was perfect.

I'm going to have to re-Chrono the load, but there's no way it's going that slow. Something else is going on. I'll also put the scope on my gunsmith's board and check tracking and click values.