adjusting for wind and drop at long range .308?


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1858rem
January 2, 2009, 04:31 PM
i was kinda lookin for a table that could show wind adjustment and drop for .308 rounds..... honestly though i dont think they help enough because i have no idea how hard a 10mph wind really is. i have been shooting cheap federal 150g soft point from walmart and still get really tight groups, so far every hole touches at 100yds and within 3/4 or so at 200yds... but i backed up to 300 and couldnt even hit the target(b34)... it was a fair bit of wind i guess, so i held about a foot high(im zeroed at 100yds) and on the left shoulder to counter the wind and missed 2/2 times and could not even see where i hit! if it shoots so tight what might i be doing wrong? im shooting with a 4-16X40mm scope off a bipod...recently i readjusted to 2.75 high at 100 to extend mpbr to about 3"drop at 275yds to hopefully rule out the drop as an issue.

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1858rem
January 2, 2009, 04:36 PM
would it just be simplest/best to work back 25 yd at a time from 200 yds to see what/where the bullet is doing/going?..... also the last 50 +/- yds has about a 30ft rise so i hold just a little lower than normal right?......i think moving back is ok, but i have no rangefinder and if i have an opportunity on a deer i would like to know how to compensate without taking 5 shots to get on target lol. as far as my range i have been using a 100ft tape to measure distance, i have a mildot reticule scope that helps with estimation of distance to

taliv
January 2, 2009, 04:47 PM
http://www.eskimo.com/~jbm/calculations/traj/traj.html


my 300 dope with a 200 yrd zero is only .7 mils up. so... if you had the gun zeroed at 200 and just held up to the top of the first mildot, you'd probably be pretty dang close.

you'd be on a b27 paper even if you just used your 100 or 200 yrd zero with no hold over. and 10mph wind isn't going to push you off the paper at that range either

otoh, i've never seen walmart ammo shoot 1/2 moa. so something is odd here

KBintheSLC
January 2, 2009, 05:36 PM
http://www.handloads.com/calc/

I use this one... works well. Try some different "zeros" and see what works best.

Ridgerunner665
January 2, 2009, 05:47 PM
1.75 inches high @ 100 yards is VERY close to dead on at 200...and it will have you about 8 inches low (+ or -) at 300 with 150 grain bullets.

jpwilly
January 2, 2009, 06:50 PM
Info Straight from Federal on the Power Shok 150gr (http://www.federalpremium.com/products/details/rifle.aspx?id=33)sold at Wal mart.

At 300 yrds 10mph wind drift is 10" and drop at 8.8" with 200yrd zero. Easily putting you off target with wind and 100yrd zero.

1858rem
January 2, 2009, 09:32 PM
well its a remington 788 model with about a 20" barrel... 22" if you include the breech its all in excellent condition, spotless really. i zeroed it at 100yds it hits about 1/2" high at 200yds and at 300 yds i think it must be the wind cause i cant hit a thing!... i saw something about its not like MOA where if you have 1" at 100 than 10" at 1000, but it is a square, so 1" drift at 100 translates roughly to 100" at 1000yds so ill try a little more hold for wind than i expected. i measured my group from 100 yds and it was 1/4" center to center.... all my other 100 yd shooting was one shot, and adjust to zero in the new scope... always dead on though.... today at 200 i shot about 1", sorry but due to 75 cents/ shot i was only shooting 3 shot groups.:o....i [B]rezeroed to 2.75@ 100yds[B] for MPBR of about 275, only 3" drop but that is not working because of the odd rise all the way untill 200 yds.

this is my first centerfire rifle, the hold, how you shoulder it and squeezing off each round is no different than 22 mag right? i got the same scope on all my rifles. the trigger is real heavy, im not flinching, but could it cause me to shoot high with the heavy pull? im guessing its twice whatever my stock 925m pull is.

Ridgerunner665
January 2, 2009, 10:28 PM
Thats considered a 22" barrel.

MOA adjustment for 300 yards is approximately 3 MOA...Or you can "hold over" about 9 inches. (200 yard zero)

The wind can be a real challenge...at 300 yards with 10 mph wind at "full value" the drift is nearly 10 inches.

20 mph and its nearly 19 inches.

Ridgerunner665
January 2, 2009, 10:38 PM
That said...one big problem is the bullets you're shooting.

You need boattail bullets...they fly better in the wind than the flat base bullets.

I recommend 168 grain Ballistic Tips (for hunting) if you can reload them.

If you cant reload and are only going to be shooting paper...get you some Federal Gold Medal Match ammo with either 168 or 175 grain bullets...I prefer the 168's but I'm just old fashioned that way...the 175's do take some of the guesswork out when it comes to "doping" the wind.

Hornady also makes some decent match ammo...

The further you shoot the more important the "little things" become.

1858rem
January 2, 2009, 11:01 PM
i got two boxes of hornady 165g psp or sp, i dont remember, at 20$/100, i did not know boattail helps in the wind, mostly just plinking relativly cheap since im gonna start reloading Real soon, so what are some good(preferably less than 30$/100 though) boattail in the 168-175 range?... i got some of my stuff today dies, bullets, primers, powder, but NO shellholders! i forgot the one for my press and all my .204 stuff is on backorder, plus my shellholder for the hand prime in .308! midway is busy i guess.



i think i read about fmj not being as accurate as hp/ballistic tip because of weight distribution, so i guess that rules out the pointed soft points i got for long range, but would they still do ok at 300-400 if i ever get on paper....wich if i hold about twice what i have been i may actually do!!!

jpwilly
January 2, 2009, 11:03 PM
1858rem, I have a small stash of the Fed Power Shok myself. Just look at the tips of those things all mangled up. They aren't going to fly straight for long. Good bullets will offer much better downrange performance. I reload those cases once I shoot em up.

Ridgerunner665
January 2, 2009, 11:06 PM
Match Bullets...Sierra and Nosler Custom Competition...both about $30 per 100,Noslers are a bit cheaper than Sierra yet shoot just as good...and sometimes better but Nosler only makes a 168 grain in that bullet. If you want 175 grain Sierra is the one.

The Ballistic Tips I mentioned are about $18 per 50 and will serve you well for hunting with a 308 (just in case)

300-400 yards is within the realm of possibility with hunting bullets...but the accuracy is not going to be anything to write home about.

rangerruck
January 2, 2009, 11:51 PM
that is a fabulous freakin rifle, I would put it up a much more expensive target rifle anyday of the week!!!! That being said, there is not much of a drop off, from 200 to 300 yds, in either speed, nor wind deflection. i would aim at the same zero point for 100 yds, and then correct when you see the hole in the paper, you will need some 20 or 30 x power binos. Typically, a 5 inch hold into the wind, if you have a 10 mph crosswind, will do pretty close, from 200 to 300 yds. Same for holdover.

Ridgerunner665
January 3, 2009, 12:03 AM
Not much of a drop off???

The 308 drops around 9 inches from 200 to 300 yards (with a 200 yard zero) and the wind drift is about 10 inches at 300...How is a 5 inch hold going to do him any good??? He will never hit the paper with that.

I do agree with you on the 788 being one of the best though.

stubbicatt
January 3, 2009, 07:30 AM
There are a number of useful and inexpensive aids available to highpower "cross the course" competitors which chart out your wind corrections and comeups. I recollect a little spiral bound book with that information available from Champion's Choice about 15 years ago.

There are probably even better aids available today.

Redneck with a 40
January 3, 2009, 10:38 AM
With the 180 grain loads and a 200 yard zero, the bullet will drop 9.8 inches at 300 yards, this is according to Winchester's data. Wind drift with a 10 mph wind is showing about 2.5".

Ridgerunner665
January 3, 2009, 10:45 AM
2.5 MOA maybe...not 2.5 inches at 300 yards...the ballistic coefficient would have to be something like 1.5 (just a wild guess...but you get the point)

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