Rifle Scopes Millett TRS-1 ranging formulas

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Airbrush Slinger
Full Member
Minuteman
Jan 25, 2009
623
1
Galivants Ferry, S.C.
#1
As most of you guys who have Millett TRS-1 glass know, the 10 power setting is not the correct setting to range a target. You have to set the zoom to about 11 power for proper ranging.

I was crunching numbers to obtain a multiplier to allow me to mil a target at maximum zoom. I came up with 39.194 as a multiplier.

The standard formula for yards..
<span style="text-decoration: underline">target size (in in.)X 27.778</span> = Range
size of target in mils

Max zoom formula for yards..
<span style="text-decoration: underline">target size (in in.)X 39.194</span> = Range
size of target in mils


If you use a hold over for your shot, you can use 1.411 as a multiplier of your mils to get the hold at max zoom.

Example.. If you have a 100 yard zero and hold 2 mils for 350 yards, multiply the 2 mils by 1.411 to get 2.82 mils. Your hold for 350 yards with the scope at max zoom.

If you dial your elevation this is not as helpful.

Some of you may have figured this out, but I figured I would post it.

I know, I know... If I had Schmidt, Us OPtics or Leupold glass I wouldn't have these issues...
laugh.gif
 
#2
Re: Millett TRS-1 ranging formulas

You have got to be f--king kidding me. I have a TRS-1 I'm sending back becuse he windage shaft is bent. I never even got to mount it.

Now you saying the 27.778 isn't any good.

I read the scope had a indication you would be at 10x ( just checked mine and it does) but isn't the ranging still supposed to be done at the highest magnification ---16x?
 
#3
Re: Millett TRS-1 ranging formulas

Millett says 16x for the New Gen TRS-1....Thats what I read anyway from their website and the manual I have but then again they are also advertising the TRS-1 (mine) to have 1/8 MOA clicks but mine is 1/4 moa...Fucked me up so i had to go back and re-read EVERYTHING
 
#4
Re: Millett TRS-1 ranging formulas

I just found a TRS manual and downloaded it. Damn, your right it does say range using 10x.

I know I read a review ( actual article not a post) someplace and the guy was using 16x for ranging. Said it was a good scope for the money and he did range and shoot using 16x.

I remember that because he wrote about there being an indicator at 10x and wondered why they would have one there for know reason.

If I can ever get this one sent back and get a replacement I'll have one more thing to figure out now.


This whole TRS thing is really pissin me off. Correction, I'm really pissed at myself for buying one.
 
#5
Re: Millett TRS-1 ranging formulas

that was probably Mels write up. He was useing a old pre production scope, it was closer to the Buck gold then the TRS they make now.

howdy
 
#6
Re: Millett TRS-1 ranging formulas

yep, what he said. you see my frustration as i tried to learn as a newbie with conflicting info. i may be wrong, but if you do the yardstick test at 100y to check the mildot accuracy, you will be able to tell if 10x is the right power to set the scope on for ranging with the reticle. even if its 11x or 9x you will know where you need to set it to use the standard math. but the formula for 16x should come in handy.

and on that subject, i was told there would be no math questions on this test

pyro, keep on bushnell. they finally sent me a label to ship my scope in for free to get repaired or exchanged for one that (fingers crossed) works
 
#7
Re: Millett TRS-1 ranging formulas

It's always a good idea to check any scope you get to make sure it is subtending correctly. Put a long piece of paper with marks 3.6" apart at 100 yards and adjust the power until the mils are on the marks. Now check the power ring and mark it if you need to so you know at what power you need to be on for the mildots to subtend.
 
#8
Re: Millett TRS-1 ranging formulas

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">It's always a good idea to check any scope you get to make sure it is subtending correctly. Put a long piece of paper with marks 3.6" apart at 100 yards and adjust the power until the mils are on the marks. Now check the power ring and mark it if you need to so you know at what power you need to be on for the mildots to subtend. </div></div>

+1....I made a sheet in AutoCad with solid grids at 3.6" and dashed grids at 1.8". I marked my magnification ring where the mildots subtended 3.6" and 1.8" if I want to do lower power shooting. I have a 1st Gen TRS-1 I bought used and it's doing fine. The 3.6" setting is at just under 16x and the 1.8" setting is at just over 6x. I am satisfied with the performance for what I paid, but am saving my expense report $$ and overtime for a higher quality scope. It completely washes out the FOV if in low light and the illumination is on any setting, so I may send it back for warranty repair/replacement.
 
#10
Re: Millett TRS-1 ranging formulas

Another option is to actually go out and range 10-20 targets at various lasered distances. Reverse mil to calculate subtension for each reading. Then average all those calcd. subtensions to get a VERY accurate 100 yd. subtension--probably to the hundredth of an inch...i think. If this theory is true, then it should be more accurate than taking a single subtension measurement at 100 yds. or 50, whatever range. And do it at the optics highest power to give the most accurate (smallest "subtension unit"), as the original poster recommends (me too). His 100 yd. subtension between dots must be 2.55 inch per hundred yds. (IPHY) at the optics highest power (which according to my calcs should be 14...right?).

IMO that's the best part of 2nd focal plane reticles--the ~inversely proportional nature of subtension vs. magnification. I've actually seen this improvised in the field to make shots that i never would've thought possible, and to calculate tgt. sizes or ranges that blew my mind for their accuracy.

I use my 6-18x Nikon Buckmasters MD at 18x where it subtends 2.4 IPHY (mils at 12). The Nikon catalog gives all this info and is actually one of the best Tech. Spec. pages of any of the catalogs.

Another nice thing about the 2FP MD system is that the dot size maintains the same relative subtensione to the dot to dot subtension (if it's a .2 mil dot it will still be .2 of whatever the dot to dot subtension is at any power). That's nice too!
 
#11
Re: Millett TRS-1 ranging formulas

Hello All

I am the guy that designed the TRS. shoot me if you will.....

As to the manual, we printed lots and are still using them up. since the TRS first came out there has been several up dates and improvements. Alot of you out there just had to have 1/4 moa clicks so we made that change, then others just had to have mil clicks so we made those. From a pure tactical scope the TRS has transfromed into a everything scope for some shooters.

The detent is at 10x and that is where the Mils are 3.6 " at 100. As there can be some slight errors in the power zoom you may find exact mil at one side or the other of 10x. for most shooting this will not be a problem, as couple .1 will not make much difference at 1000. as it will only add up to 2 inches error.

At 16X the mils will be about 2.2 " at 100 yards if that will help.

Mils are measured between center of the dots or on the mil dot bar reticle in the TRS from the bar to the center of the dot. You can also go from the top of one dot to the top of the next dot and that will work also. from the bottom of one dot to the top of the next bar will be about 3.1" at 100yd at 10x.

hope I have cleared up a little on this subject.

Good shooting

Steve
 
#12
Re: Millett TRS-1 ranging formulas

Much of the information you posted is available in the manual online on the Millett web site.

As Rob says, you will need to confirm the power setting at which the mils are accurate. The manual is right here:

http://www.millettsights.com/images/instruction_sheets/Millet_TSR_Manual.pdf

It's always a good idea to RTFM.
laugh.gif


I heartily approve of manufacturers who are conscientious enough to post their manuals online.

 
#13
Re: Millett TRS-1 ranging formulas

Steve,

Is the new mill mill version supposed to ranges at 10x also?

I understand the difference between the mil reticle and MOA or mil elevation but what I want to know is, is the newest versions or are all TRS scopes manufactured to range accurately ( without weird math) at 10x
 
#15
Re: Millett TRS-1 ranging formulas

Interesting--my calcs with the info the OP originally gave should mean that the highest power would be very close to 14. Millett says that the subtension at 16 is as calculated--2.25 IPHY. Oh well--as usual test it and see...that is, for those that want the highest degree of accuracy the scope offers for rangefinding capability.
 
#16
Re: Millett TRS-1 ranging formulas

If the mils are correct at 10 power, which means that at 100 yards the distance between them is 3.6 inches or 1 mil, then at 16 power you have:

3.6*10/16 = 2.25"

If the power ring is not correctly calibrated, though, it'll be a little different. Test and find out.
 
#17
Re: Millett TRS-1 ranging formulas

I got the numbers From an actual measurement test. Stretched a tape on a target and used the 3.6" per mil to obtain the correct setting for the standard formula. (approx 11 power)
Then followed suit on the max setting. Settings may differ from scope to scope.

The max setting worked out to be about 14 power.

Just my .02...
 
#18
Re: Millett TRS-1 ranging formulas

OK - I have seen that kind of miscalibration on other scopes. In fact, one set of a major manufacturer's scope I tested which had SFP reticles designed to mil at the highest setting could not be used correctly - the power ring didn't go high enough for the mils to be correct.

Testing turns up those kinds of problems. Good job!

 
#20
Re: Millett TRS-1 ranging formulas

Hello

the mils are set for 10x. I rounded the 16 setting to 2.2 which is as good as I can hold.

the FFP is something that is possible in the future, send bushnell emails that you want one and they will see the demand. And you are right if you have FFP you do not have to worry about the zoom setting, but remember the size of the reticle grows as the target grows with the power increase, for small targets this is not good. the reticle is bigger then the target hard to hit small targets. Remember in the 50s and 60s the common scope was FFp and shooters did not want them for hunting. History repeats it self.

good shooting

Steve
 
#23
Re: Millett TRS-1 ranging formulas

millett,

I was actually one of the shooters that used an FFP scope in the mid-70's. The problem was not the FFP concept but reticle design. A German #1 type reticle with fat post and crosshair was a problem in that it appeared too small at 2x (when you thought you wanted it large) and it appeared too large at 6x when you thought you wanted it small.

The real reality is you don't need FFP variable to shoot at something at under 50 yds. It's the wrong tool for the job. Further, the relationship of target to reticle in a FFP scope is the same throughout the power range. So if your FFP covers a 3" target @ 3x, it will cover the the same 3" @ 18x. It does not cover more or less of the target. The target grows in the same relationship as the reticle grows.

There is a balance that must be struck in designing a FFP reticle, more so than in a SFP scope. This can be compensated somewhat by adding illumination to an FFP.


In some @ home low light tests using live deer in a field next to my house, I did a few years back, I compared a Zeiss 30mm SFP, Nikon 30mm SFP and a Leupold 1" SFP, and I found that although the 30mm tubes and 42mm to 50mm objectives on the Zeiss and Nikon where a bit better, the real differences were the large German #4 reticles on the Zeiss and Nikon, compared to the standard Leupold Duplex. I could still see the deer with the Leupold, but I lost the reticle a full 5-10 minutes earlier than with the Zeiss and Nikon.

Bottom line is, if your never going to use your reticle to range, or do holdovers/unders, then you don't need an FFP scope with a ranging reticle. Better to get a reticle that can be seen in low light, and then add illumination for max performance.

However, if you have any aspirations in actually using your reticle for ranging, and hold offs, overs/unders et al, then good turrets and FFP is a must to effectively use that tool. Add illumination for low light scenarios, and you are GTG.
 
#24
Re: Millett TRS-1 ranging formulas

Steve,

My first generation TRS-1 has no dot-bar reticle, just 5 dots on each crosshair. I put a 3.6" grid at 100 yards (measured) and it subtends 1 mil, dot center-to-dot center, just below the 16x setting. Is this correct for the scope's vintage (ser. # 6060080)?
 
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