Best zero for 45/70

[brstevns]

Was not for sure were to post this question, What is the best zero for a 45/70 using 405gr factory loads with a scope sighted rifle? What worked best for you?

[btroj]

There is no right answer. What is the max range you will be shooting? What velocity? Too many variables for a precise answer.

I go with on at 100 for most of my 45-70 hunting. I am not likely to shoot past 125 so it works for me. It also keeps me from hitting too high in close.

When I went to Canada last spring for bear I knew the shots would be 15 to 35 yards so I sighted dead on at 25.

The beat zero is based on too many factors to have a single right answer. This is where a ballistic software is a big help. Put in the load info and see what you can get out of it. Most 45-70 loads will be ok to 125 without too much holdover if sighted on at 100. Past 125 you need to know the range and your bullet drop to make a clean shot. And lots of practice.

To me the 45-70 is a 125 yard gun. If I need to shoot farther I go to a different cartridge. Since most of my hunting is closed ranges than that the Marlin is my first choice.

Brad

[brstevns]

I plan on a 405 to 430gr cast bullet at 12-1300fps no shots past 125. where are you hitting at 25 and 50 yards with that 100 yard setting?

[btroj]

I don't have exact info but on at 100 might be a couple inches high at 50 and close to on at 25. With the load you are looking at you can be on at 75 or so. This would put you maybe 1 inch low at 100 and no more than 2 inches high at closer ranges. It really is at longer ranges that things get bad. Try to be on at 150 and your midrange height gets a bit much. I don't want to be 5 inches high at 75 to 100 just to be on at 150.

[TCLouis]

The ballistic calculator can be your friend if you test fire and confirm the calculated results.

Plug in 0.225 for a BC and then plug all of your other parameters into the appropriate spots and it will give you some guesstimates you can use to start working with..

http://www.handloads.com/calc/

[brstevns]

Sorry for not getting back sooner. Thanks for the information it was a very big help

[BrokenFang]

I shoot 520 grain round nose at 1350.the 32inch barrel is zeroed at 200 the 22 inch barrel is zeroed at 50 yards. these are handi rifles

[onesonek]

I agree with the others on the ballistic program. I sight mine in with a PBR on a 6" target. If your not familar with PBR (point blank range), and my desired 6" target, the boolits trajectory will be no higher or lower than 3" with a center hold,,,,(ideally). Naturally there will be 2 line of sight crossings or zero points. Velocity and the BC, of the boolit and some atmospheric factors determine what those are. The ballistic program will give you PBR if it is set up that way. If you like the idea of the PBR and can't find an online program that gives you that data, let me know and I'll run some number for you... just need a close approximation of your velocity.

[Tazman1602]

I plan on a 405 to 430gr cast bullet at 12-1300fps no shots past 125. where are you hitting at 25 and 50 yards with that 100 yard setting?


br --

Here's the ballistic table for a load of mine. 45-70 405gr at around 1290fps

Art

Ballistic Data
~~~~~~~~~~~~~~~
Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect
0 yds -1.50 in 1290 fps 1422 fpe 0.000 sec 0.00 in -1.50 in 0.00 in
25 yds 1.06 in 1248 fps 1331 fpe 0.059 sec 0.66 in -0.43 in 0.14 in
50 yds 2.22 in 1209 fps 1250 fpe 0.120 sec 2.72 in 0.10 in 0.64 in
75 yds 1.89 in 1174 fps 1178 fpe 0.183 sec 6.26 in 1.03 in 1.50 in
100 yds 0.00 in 1141 fps 1113 fpe 0.248 sec 11.38 in 2.38 in 2.67 in
125 yds -3.57 in 1112 fps 1056 fpe 0.314 sec 18.16 in 4.20 in 4.16 in
150 yds -8.88 in 1085 fps 1005 fpe 0.383 sec 26.69 in 6.52 in 5.95 in
175 yds -16.04 in 1061 fps 962 fpe 0.453 sec 37.07 in 9.35 in 8.02 in
200 yds -25.11 in 1039 fps 922 fpe 0.524 sec 49.36 in 12.74 in 10.36 in
225 yds -36.20 in 1019 fps 887 fpe 0.597 sec 63.67 in 16.72 in 12.96 in
250 yds -49.33 in 1000 fps 855 fpe 0.671 sec 80.02 in 21.29 in 15.80 in
275 yds -64.56 in 983 fps 826 fpe 0.747 sec 98.46 in 26.49 in 18.84 in
300 yds -82.05 in 967 fps 799 fpe 0.824 sec 119.18 in 32.36 in 22.16 in
325 yds -101.90 in 951 fps 774 fpe 0.902 sec 142.24 in 38.94 in 25.73 in
350 yds -124.11 in 937 fps 751 fpe 0.982 sec 167.67 in 46.24 in 29.52 in
375 yds -148.70 in 923 fps 729 fpe 1.062 sec 195.48 in 54.26 in 33.50 in
400 yds -175.67 in 910 fps 708 fpe 1.144 sec 225.67 in 63.01 in 37.64 in
425 yds -205.30 in 898 fps 689 fpe 1.227 sec 258.52 in 72.59 in 42.03 in
450 yds -237.27 in 886 fps 670 fpe 1.311 sec 293.71 in 82.91 in 46.52 in
475 yds -272.07 in 874 fps 653 fpe 1.396 sec 331.73 in 94.10 in 51.27 in
500 yds -309.73 in 863 fps 636 fpe 1.482 sec 372.60 in 106.20 in 56.25 in
525 yds -350.27 in 852 fps 620 fpe 1.570 sec 416.36 in 119.21 in 61.46 in
550 yds -393.72 in 841 fps 605 fpe 1.659 sec 463.03 in 133.16 in 66.86 in
575 yds -440.09 in 831 fps 590 fpe 1.749 sec 512.62 in 148.04 in 72.45 in
600 yds -489.41 in 821 fps 576 fpe 1.840 sec 565.16 in 163.89 in 78.21 in
625 yds -541.68 in 811 fps 562 fpe 1.931 sec 620.65 in 180.70 in 84.12 in
650 yds -596.92 in 801 fps 549 fpe 2.024 sec 679.11 in 198.49 in 90.17 in
675 yds -655.62 in 792 fps 536 fpe 2.118 sec 741.03 in 217.41 in 96.48 in
700 yds -717.54 in 783 fps 524 fpe 2.213 sec 806.17 in 237.41 in 102.97 in
725 yds -783.05 in 774 fps 512 fpe 2.309 sec 874.90 in 258.59 in 109.70 in
750 yds -852.19 in 765 fps 500 fpe 2.407 sec 947.25 in 280.98 in 116.67 in
775 yds -924.98 in 756 fps 489 fpe 2.506 sec 1023.26 in 304.61 in 123.85 in
800 yds-1001.47 in 748 fps 478 fpe 2.606 sec 1102.97 in 329.48 in 131.23 in

[peerlesscowboy]

Was not for sure were to post this question, What is the best zero for a 45/70 using 405gr factory loads with a scope sighted rifle? What worked best for you?
Assuming you're talking big game.........or at least large varmints? 100 yards.

John C. Saubak

[Crusty Deary Ol'Coot]

AS stated, there can be no single correct answer to the question.

As noted on the replies to this post, I see that most shooters are in the 1200 - 1500fps range with their loads, while I am currently at 2290fps with a 355gr LBT/WFN boolit.

I am not trying for the higher velocities, but will not turn away from them if I can also find the groups I want at that level.

I also hope to have my RUGER 45/70, be a very able 200yd rifle, and the higher velocity will help in that respect.

I have a bunch of testing yet to do, but did take my first cast boolit critter with the 45/70 this past Fall. 100yds. bang/flop!

That boolit was flat AWESOME!!!!!!!! in the results department.

Ask me again in a year, and I hope to have a lot more usable information and maybe a few more critters.

Keep em coming!

Crusty Deary Ol'Coot

[brstevns]

Thanks again that is a lot of information. thanks Tazman1602 for listing all that infor. Was just what I was looking for. What a great forum

[onondaga]

I use a free real-time online calculator, plug in my values and manipulate the "SIGHT IN AT" value until I get the path I like best for the distances I hope to hunt at. You have to measure the distance from your bore center to your scope center. You can measure your scope tube diameter, your barrel diameter and the space between then do the arithmetic to get your sight height for the distance from your bore center to your cross-hairs. The other values you can look up and set the intervals on the path for whatever you want also. Fun to play with trying different sight in at distances and press "calculate"to see how it effects how high or low your impact will be anywhere along the path.

http://www.handloads.com/calc/index.html

I call the page, "External Ballistics for Dummies" in my favorites list and use it often. I remember the sniper headaches my slide rule and formulas gave me doing this in the 1960s when I wanted to optimize a mid-range trajectory related to line of sight and point of impact before computers and software.......aaaaaaaaagh! and then there is windage, don't get me started, I'll drink again.

gary

[Crusty Deary Ol'Coot]

Onondaga,

How do you guesstimate the "B.C." on something like a .459, 355gr LBT/WFN?

I can look at my loading books and get some kind of idea, but suspect I will be off a fair amount!

Keep em coming!

Crusty Deary Ol'Coot

[NickSS]

Personally I have three sight settings on my 45-70 that I use for hunting. I have open iron sights set at 100 yards zeroed for my load. I canflip up the barrel sight and the elevator is zeroed to 150 yards. I then have a hunting tang sight that I can flip up that is zeroed for 200 yards. By practice I know the hold over and under for intermediate ranges. I also have a sight chart on my gun that has been actually shot at 25 yard increments out to 600 yards so I know the tang sight settings for all ranges. Now when I mostly hunt heavy timber with a marlin I set my sight at 100 and forget about the rest but when I go hunting on the plains I use my sharps with the barrel sight and tang sight alonf with a laser range finder. I have killed a couple of mule deer at 200 + yards and one antelope at a lasered range of 425 yards. It was standing still and no wind condition so I adjusted my tang sight, put the pots just under its chest and let fly. The 400 gr bullet hit it midway in the chest cavity and went clean thru. The animal ran about 50 yards and fell over dead. That is the longest game shot I made with a 45-70 and I would not even attempt it unless I had zero wind and a laser range finder as well as I load and rifle I was totally familiar with.

[nanuk]

I have a Ballistics Calculator that I got years ago. it works good

one thing I do also, is I use my load group to calculate the best PBR.

in other words. as an example, lets say the Calc sez a 150gr .277 Jboo has a BC of .425.

and after punching in my speed of 2800, sighting 1.5 above bore etc... it shows a PBR of 325 yds. for a 6" target/3" max height. BUT, I get 2" groups, so review my data and by extrapolation I can change my PBR so my 2" group is taken into account, and then I use that sight in distance.

(edit: I do this by looking at the max height distance and including my group. so say, at 185 yds, max height sez 3" I know at 185 yds my group will be 1.85" from center, so my max height MIGHT actually be 4.85 inches. So I rein in my PBR until I get a comfortable Max height (3" for deer, 6" for Moose/elk) edit end")

that way I KNOW I can hold dead center (IF I can hold) and guarantee a hit.

it shortens the distance, but it also does not give one a false sense of reach.

also, Play with the settings. sight height, angle of shot, wind.....

really opens up the eyes.

[onondaga]

.211

The link in my post above, #13 has software to do that on the left. Did you go there yet? I entered your info and got .211 , you just enter the caliber, weight and approximate shape from the selection, then click "calaulate". Consider that you can be off 25 or more on BC and it will not change your point of impact by but a little more than the diameter of your bullet at a couple hundred yards, that is if you can shoot that well to notice it at 200 yards. The human skull is about 1-MOA at 500 yards, What are you shootin at guy?

Now you know BC varies with range and velocity, so you will have to do a lot of learning or ask Mr, Wizzard and tell him the range and velocity there too.

Gary

[Crusty Deary Ol'Coot]

Well, I looked at the section to find the B.C. but no options were given for a cast WFN boolit in 45cal.

Thanks, Crusty Deary Ol'Coot

[onondaga]

I guess it didn't make any sense to you that a SWC or HP would be the closest shape selection to a WFN to use with the calculator. I can't help you with sense of shape perception. Besides, altitude or temperature has more of an effect than that precentage of an error in BC. Like I said, What are you shootin at?

Gary

[onondaga]

PM me with your honest 10 shot group size at 50 yards and the muzzle velocity of that 405 in your rifle along with your cross hair height above bore center and I will calculate your best zero and tell you why. Everybody is dancing around here.

Gary

[onondaga]

Most hunting guides and guide manuals will recommend a specific sight-in of 2 inches high at 50 yards for large bore rifles with heavy bullets. This generally puts the zero at 130 or so yards and little hold over is needed at ranges continuing to the point where the foot pounds delivered drops below 1000.. This gives the shooter an advantage because the plus 2 inches at 50 yards is very easy to visualize at that distance on game animals and the same load will generally also be about 2 inches high at 100 yards. That is also an easy distance for a shooter to guess at. The distance from 100 yards to zero point of impact and beyond to a range where your group size is 75% of a given 10 inch vital area of deer size targets is about 180 yards for the 45-70. After that energy and bullet drop become very pronounced. So the 2 inches high at 50 yards is the best zero for the 45-70 with its effective range and power. For Humane harvesting of big game consider the range at which your load delivers 1000 ft. pounds as your maximum range.

Scope sighting in at 50 yards is best done on a large target with a small 1 inch diameter bulls-eye to center concentration for shooting and a small penciled one inch circle that is located 2 inches center to center above the main bulls-eye. If you can get your shots in or touching the small penciled circle above the main bulls-eye at 50 yards, you are in terrific shape with a 45/70 and its effective range. For shooting beyond effective range, compute a drop chart and memorize it and use a rangefinder..Big heavy bullets drop fast beyond their effective range.

Thanks for the nice PM Crusty.

Crusty, I hunt deer and bear with a pet hand load that approximates the 45-70 factory load in a .458 Win Mag Colt Sauer Grand African scoped sport rifle and this sight-in and zero method has given me good confidence hunting.

Gary

[Crusty Deary Ol'Coot]

As I have yet to solidify my load for the #1, I have not done any target work at anything other then 100yds.

This past Fall, I went into the field with the groups centered at about 4" high at 100.

As stated, I have not checked the loads out closer or beyond and probably will not do so until I have gone beyond the present testing phase.

For years, I have always sighted in my rifles so that I used no hold, over or under, out to extended distances. Just held center of kill zone.

This was however with rifles/loads much in excess of the velocities of my 45/70.

If I can continue to maintain velocities in the 2000 - 2300fps range with the 45/70, I should be able to use a like system, only at a lessor distance.

I may need to change boolits to get the groups I desire, and if so, velocities may well decrease, especially as a change will likely mean a heavier boolit then the current 355gr..

Time will tell. Have one more powder I am thinking of trying, and then possibly I will need to check out other boolits.

Keep em coming!

Crusty Deary Ol'Coot

[onondaga]

I use the Lee 457-340 RN-F . My as cast diameter is .460 after Leementing a few times. . My velocity is 1610 fps and best 5 shot group size is .782" at 50 yards. My 10 shot group size at 100 yards is 1.6 " I am waiting a plain base checkmaker from member Pat Marlin for this bullet and am very hopeful that I will be able to increase velocity to 2K and obtain similar or better accuracy with a gas check.

Consider that bullet if it will fit your rifle, the bullet path is significantly flatter than a 405 and the foot pounds is sufficient for polar bear or grizz . My rifle was obtained as a back-up when bow hunting Musk Ox in big bear country but has ended up being my favorite rifle with cast boolits.

Gary

[Crusty Deary Ol'Coot]

Onondaga,

OK, spent some time with the program, and marked it as a favorite in the pooter,

I see where you arrived at the .211 B.C. and I just need to study the instructions a bit more and do the scope to bore measurement etc.

Tried to print out the instructions, but no luck, so will just need to study the info on the site.

As per present velocity, at this point, I seem to still be WELL over the 1000ft lbs level at 200 yds. - like 1900+ - and although I still need to study this thing out some more, it looks like a shot at that range should be a cake walk, providing #1 I do my part, and #2 I get the groups sized down about half of what I presently have.

As said earlier, need to test some other powders, but will also look at other boolit weights and styles.

Lloyd, seems to like the 405 RCBS very well, and I do have a mold for that - hate single cavity molds! - but he also seems to really favor LFN styles, feeling they group better then the WFN.

later,

Keep em coming!

Crusty Deary Ol'Coot

[onondaga]

Crusty,

Don't forget the 350 gr. RanchDog if you are looking for a new bullet. I'd love to have one of these molds:

http://www.ranchdogoutdoors.com/index.php?main_page=index&cPath=1_5_14

BC is .3143 for that one and it casts at 355 grains and drops at .460" Run the calculator on that one!!!! I bet you could get that one to 2000+ fps and have good accuracy.

Gary