Angle cosine or angle degree indicator , which is easier to use ? Also, do they require a picatinny rail ? At present I have the one peice Talley base and rings for my Rem 700 STW, so how would I mount an angle indicator ?

If you don't want it mounted or you want to go the cheap way just use a protractor with a string and a weight at the end(such as a pen or pencil) or Google "slope doper". These are cheap alternatives that work.

Check the ballistic software that you normally run and see which it asks for. The version of Exbal that I use ask for the Incline Angle in degrees. Others will know better than I but I think if you use a drop chart and just do the math for the angle the Cosine would be a better choice. Do a search. There was a thread that really got into this just a while back.

I'd vote "cosine" units on the device -- You can use software or prepare you charts to handle the cosine value with little to no extra effort... HOWEVER, if you ever find yourself without your Pocket PC/charts/calculator and have to do the math "by hand" in the field, simply multiplying by the cosine value supplied by your angle measuring device is a helluva lot easier than multiplying by the square root of (1 - sinĀ² X), where X is the angle in degrees read from your device At least for me anyway... I guess you could commit cosine tables to memory -- but who has braincells for that?

I hope this helps. A good advice from former post is for you to make sure that the ballistic program you plan on using will handle your choice of angle reading. My version of Exbal does both on my pocket pc and LoadBase 2.0 from Patagonia Ballistic does also both. Good luck!

Really the same -- at least with the Sniper Tools version, both versions are numbered in about 5-degree increments (cosine in cosine values though, obviously) -- so having a cosine out to more decimal places isn't going to be any more accurate. Calculating the cosine from degrees gives a more "precise" number in terms of having lots of numbers after the decimal point, but it's not any more "accurate" due to the measuring limitations of the device. Not to worry though, it's still has plenty of "resolution" for our needs. If you started to try to be accurate down to the degree or sub-degree, you'd have start worrying about things like where your reticle is dialed when you site the target to take the angle. Fortunately, in the 1000 yard neighborhood, we're only talking an inch or two of difference per five degrees for the cartridges most of us are shooting -- so being super precise with the measurement isn't all that vital. Anyway, it really does just come down to which is more convenient for you personally to work with.

I only use degress. You can use an extra scope ring to mount the ACI to your scope. Just find one that clears the top of the action.

I prefer the cosine model myself, which saves a math step (or two brain cells, LOL) in the field, where my ACI is actually utilized. As posted above, one can always treat the cosine increments as 5o angle increments if needed and still be close enough. For about $16, USTactical markets a scope ring mount that eliminates the need for an M-1913/Picatinny rail to use with Badger's versions of the mount bracket: ACI Scope Tube Mount ETA: Meant to mention that "W" (Ward Brien of SniperTools) is allowing a group buy discount on his MilSpec ACIs over at Sniper's Hide until 6-30-08: Angle cosine indicator - Sniper's Hide Forums

Best price I've seen so far with Pic mount is: Badger Ordnance/Snipertools Angle Cosign Indicator w/Gen 2 Mount [306-73A] - $149.95 : Long Range Supply!, Precision optics & more Nightforce Angle Degree Indicator with Mount - ADIMT [NFADIMT] - $149.95 : Long Range Supply!, Precision optics & more Anybody seen a better price?

Very good prices for the setups, jmden. I like the NF mount, due to not requiring removal of the scope from the rail to install.