Hi

Well - I was banging my head against how I was going to scope this thing.

In case you missed my other post, I'm looking to put together a 500 yard target-shooter, and I was considering a sloped mount, but I couldn't figure out how MUCH of a slope to use!

Enter Point Blank Ballistics Software!

So: I look up the stats on the Winchester 168 grain hollow-point boattail match ammo, and plug in the numbers. It looks interesting AND reasonable! SO: I reset the scope-height to accomodate my huge objective (51mm!!) scope and recalculate.

Wow! LOOK!!

Code::

Load Data ~~~~~~~~~ Name: .308 Cal, Winchester Hollow Boattail, 168 grn Ballistic Coeff: 0.452 Bullet Weight: 168 Velocity: 2680 Target Distance: 425 Scope Height: 2.000 Temperature: 70 Altitude: 500 Ballistic Data ~~~~~~~~~~~~~~~ Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect 0 yds -2.00 in 2680 fps 2679 fpe 0.000 sec 0.00 in -2.00 in -0.00 in . . . 200 yds 13.88 in 2311 fps 1992 fpe 0.241 sec 10.66 in 2.02 in 2.97 in 225 yds 14.17 in 2267 fps 1917 fpe 0.274 sec 13.68 in 2.84 in 3.84 in 250 yds 14.03 in 2224 fps 1844 fpe 0.307 sec 17.14 in 3.79 in 4.82 in . . . 425 yds 0.00 in 1932 fps 1392 fpe 0.560 sec 54.39 in 14.43 in 14.79 in 450 yds -4.10 in 1892 fps 1335 fpe 0.599 sec 61.81 in 16.62 in 16.71 in 475 yds -8.87 in 1853 fps 1281 fpe 0.639 sec 69.90 in 19.03 in 18.84 in 500 yds -14.33 in 1814 fps 1228 fpe 0.680 sec 78.67 in 21.66 in 21.15 in 525 yds -20.49 in 1777 fps 1177 fpe 0.722 sec 88.14 in 24.53 in 23.63 in 550 yds -27.37 in 1740 fps 1129 fpe 0.765 sec 98.34 in 27.65 in 26.29 in . . .

Sweet SALVATION! What a great chunk of data! 14.17" high almost EXACTLY at mid-range, and 14.33" low at terminal!

Now - if I can only find a target with a 28.5" bullseye....

More importantly: In the, "Drop," column, I see that I have a total drop of 78.67"! Now: Let me see... 78.67" (total drop) divided by 5 (to scale it to 100 yards by the 'similar triangles' rule) gives me 15.734 inches! One Minute-Of-Angle at 100 yards is...

oh drat...

Ok - I remember that it's, "about an inch," but this is MATHMATICS! I want my, "abouts," to be about three decimal places!!

So: Circumferance of a circle with a radius of 3600" (inches in 100 yards) is:
2 • π • 3600" = ....
Uhhh - π = 3.14... uhhh....

Code::

How I need a drink, alcoholic of course 3 1 4 1 5 9 2 6

so: 3.1415926
2 • 3.1415926 • 3600" = 22619.467"
The number of minutes in a circle:
360 • 60 = 21600
Inches in one MOA at 100 yards:
22619.467 / 21600 = 1.047"
(Mmm - wow - that really IS, "about," an inch!!)

So 15.734 / 1.047 = 15.028

As close to 15 MOA as I'm likely to get. My gut feeling was that 15 MOA would do the trick!

Now, I have PROOF!!

To three decimal places!!!

LOL Nice math.

Notes: at 500 yards 1MOA rifle will be hitting within a 5" circle.

Also, for your paper target quest you might want to download and fool around with the PC version of PointBlank. It has a nifty little feature called PBR (point blank range) calculation that is exactly what you are trying to do here. PBR is the max distance your bullet will be no more than TargHeight / 2 above the line of site and -Targheight/2 below the line of sight. It also shows what the zero distance is for this setup.

I like it for deer where I use say a 10" PBR.


-DallanC

Hi

Great stuff! I'm going to spend some time inside the package.

Dude: You ROCK, mathematically and algorithmically speaking!

[edit] OOOH!

For a killzone of 28.50 inches:
Maximum Point Blank Range is 501 yrds
Sight in the rifle dead on at 426 yrds

Ok - I reiterate: Dude: You ROCK, mathematically and algorithmically speaking! [/edit]

Looks like you are really on your way to being a real "Hunting Nut".
Since I got my first "Modern" Savage @ 1998 (a 110 Tactical in .223) I have been sold on Savage Bolt Rifles. I ahve yet to find an out of the box rifle that can hold a candle to any I have picked up. I now have 3 10FP-LEs that I won't part with. I have totally built one up with a Kreiger .308 barrel, SSS Trigger, McMillian stock, Farrel base & rings & a Tasco Varmint 2 X 10 Mil Dot. This one willhold honest sub half inch groups with many loads.

Another semi built with the SSS trigger, modified factory tupperware stock, Weaver bases & rings and a Tasco Varmint 6 X 24 Mil Dot. This one has the factory barrel and will shoot in the 3s and on really good days has gone under .2 with many groups. This is with my loads, with Black hills REmanufactured you wouldn't want to be a varmint at any reasonable range. It would be safer at 5 yds than out at 300.

My final mod 10 is my any caliber, B & C stock, SSS trigger, Leuopold bases & QRW Rings. I have several barrels for this one and use it for most of my rifle hunting. Barrels so far are, 250 Savage, 260 Rem, 308 Win & soon to have a 358 Win also. I have been thinking of a 338-08 instead of the 358 Win as the bullet selection is a bit better.

I completely enjoy them all and would recommend a Savage Rifle over any Remchesger. Lower inital cost, better accuracy and above all extreem versitility and interchangability. What more can you ask for.

Speaking of MOA and depending on what scope you use (which i'll get into in a sec) a good estimate (kill shot) of range finding can also be done.
If height or width can be estimated with using a Mil-Dot scope (or Horus Vision which is easier yet), you take the height of the target (in yards) and divided by the height of the target (in milliradians) and multiply by 1000 which equals the distance to the target in yards.
Example:
If the top of a 6 foot tall target (2 yards) (and for argument sake a person) lines up with one dot, and his feet line up four dots down you get this........2/4x1000=500 yards.

Leupold claims that the length of their dots are 1/4 Mil (miliradian) or 3/4 MOA (minute of angle) which turns out to be wrong.
1/4 Mil= .9
3/4 MOA=.785
After a phone call i was told that "most shooters buy these scopes that mostly understand MOA and not Miliradians, so we claim a figure (in MOA) that is close, but not exact". (I was dumbfounded!)

(there may be some that think "Mil" stands for Military, well it stands for Miliradian)

BTW....i put a Lothar polygon rifled barrel on my 10 and i do pretty well holding sub MOA out to 500+ yards.

Hi

Thanks for the words.

My Ken Farrell Sav. RTS.1.10 (Round Top Short, 1 piece, 10 MOA depression) arrived today. It's a BIG, MANLY... uhhh... I can't say that any more, can I... BIG, PERSONLY piece of matte black steel! It may need epoxy bedding to the reciever. It may NOT. I'm betting it will, and besides, epoxy-bedding is just a darned nice thing to know about, so it's off to the bookstores for me.

It looks like, once it's seated correctly, it'll ride right about .31" higher than the Weaver 2-piece mounts I have snugged on right now.

I put on the Weavers because they were availiable, and if not DEAD cheap, then BADLY-WOUNDED cheap. (Drat - I've used that joke, here, before.) They fit nicely, and my steel rule said they lined up like a charm. I used them to mount my Leupold QRW rings to my two scopes: a Bushnell Banner 6-18x50 for field and an Optronics 6-24x42 illuminated mil-dot for targets.

I should PROBABLY say that I used them to RUIN my QRW rings!

I couldn't get the screws to line up through the caps to the base correctly once the scope tube was in place, it turns out. It just FELT that way. I'm going to have to knock everything apart again and see what I can salvage. I suspect... SUSPECT, mind you... that I'll be able to get one full set out of the deal that'll be clean enough (with a bit of work) to be usable.

A LOT of education for $45, I think.

If I need to buy all new rings, though, I'm going to try to trade the Bushnell 50mm bell scope in on a similar 42mm bell scope and buy medium height rings. I like a big bell (more light IN is more light OUT, right), but... SHEESH! WHO KNEW!!

I've got three Harris bipods, one each of low, medium and high, each with its own HB6 stud for quick-change mounting to the 3/8" rail slot. I didn't go for swiveled bipods, though, because I figured to mostly be shooting from a table or bench with them. In the field, I'll go hasty with a treetrunk or some grass and leave the bipods in the case.

Next thing to do is to pull off the, "factory tupperware stock," which description I love for its vividness and accuracy, which STOCK I HATE for its TUPPERWARE..ey...ness, and torque the action into its new Choate Machine & Tool Ultimate Varminter stock.

I got a partial shipment from Sears last week with a 3/8" drive, 25-250 inch-pound torque wrench that'll get the job done (Choate says to use 65 in.-Lbs. for the action bolts) after I find somewhere to verify the torque.

SO: Pull apart rings and salvage, restock, read up about epoxy-bedding scope mounts, and try again!

A couple of questions:

Has anyone used a, "Ching sling," for REAL shooting? I've been looking as slinging systems and it looks like it provides a good balance between the drag-yer-cannon-through-the-mud sling and the get-your-rifle-to-bahave-whilst-you-shoot-it sling. The Choate stock is already set up with side-swivels, and I think that, with a very little extra work, I could be Chinging right along.

I've been told to tighten the ring cap screws, "about as tight as I can get them." Well... I live in a FRAGILE world. "About as tight" for me is WAY past stripped out, so that is TOTALLy wrong. I've also been told to tighten the ring-mount screws the same way! Same deal!! Another source said 65 in.-Lbs. on the ring-mount screws, so there is, SOMEWHERE a torque spec on the cap screws too!

Understanding that: Does anyone have any experience with micrometer click torque SCREWDRIVERS? I'm kind of interested in putting one in my range kit for periodic checking of screws. Am I over-thinking this? Should I just put the thing together with Black Death LockTite and be done with it??

Thanks for the help, and more soon!!

Al, I don't know much about the sling, Nor have i used a mic. screwdriver.... but i will give you some good advice on tightening screws and mounts. It is easy to over tighten but a good way not to strip is by using loctite on the screwes first, snug what ever it is you are tightening, then with another 1/4 turn and no more than 1/2, you are in the good.
Just make sure the threads are clean and when tightening because it should be smooth up until sung (which snug usually is done by using three fingers and your thumb for initial tightening, then your whole hand).
I know everybody is and has different ways to do things, and this is how i have been doing my smithing for many, many years. While the way i do it is ok for some, it's not for all but i hope it helps!

Put a little of that Loctite in the rings too...It will help keep the scope from moving during recoil...