Zeroing 300 Blackout SBR; Super vs Sub?

[mammynun]

How are you guys handling the ballistic difference between super and subsonic ammo? As of now the T-1 is zeroed for supers @ 50yds, once my forms 1 and 4 come in I'll be shooting mostly subsonic and will rezero for that.

For that matter, what are you all using as a zero distance and why? Please include your ammo choice(s)...

I'm shooting a 10" Noveske with an Aimpoint T-1, mostly Gunn SOST and Remington UMC supersonics, and Gunn 220gr and 180gr subsonics.

Here's the dirty, filthy wench taunting me as she languidly exposes her charms... waiting for me to stick a UBR on her bum.

I need a shower.

 

[JTinIN]

With a low power scope with mill dots then you zero one load using the cross hair and see where the other round hits. Hopefully a dot or two up or down.

With a scope with calibrate external knobs one zeros one load, sets the controls to 0/0 and then re-zeros and writes down the second setting. On my 338LM the settings are on the bottom of the mag on a tag.

With your setup if you can get the HV to zero at 100 yards and the sub sonic to zero at some other range, then would go with that. Windage differences tend to be a bigger issue than elevation. You can also use the tip and bottom of the red dot for fine (tin can jumping) differences but the red dot works best zeroed at the center.

One more option with your setup is zero the load you use the most with the red dot and zero the other load with the iron sights ... just turn off the red dot and use irons when shooting say high velocity.

 

[mammynun]

With a low power scope with mill dots then you zero one load using the cross hair and see where the other round hits. Hopefully a dot or two up or down.

With a scope with calibrate external knobs one zeros one load, sets the controls to 0/0 and then re-zeros and writes down the second setting. On my 338LM the settings are on the bottom of the mag on a tag.

With your setup if you can get the HV to zero at 100 yards and the sub sonic to zero at some other range, then would go with that. Windage differences tend to be a bigger issue than elevation. You can also use the tip and bottom of the red dot for fine (tin can jumping) differences but the red dot works best zeroed at the center.

One more option with your setup is zero the load you use the most with the red dot and zero the other load with the iron sights ... just turn off the red dot and use irons when shooting say high velocity.

Well duh! I'd like to think that I'd have come up with that answer by myself, but ! I really didn't want to scope it, though I do like my 1-4x on my SPR-ish build. I also have an EoTech, but I'm don't think the 65moa/2=32.5 reticle division would be very useful for this type of application.

Thanks for saving me some ammo!

 

[42769vette]

the real questions is how long did you have to wait on a 10 inch blackout barrel. ive been looking for some instock for a few weeks, but im about to just get on somones list

 

[bigcraig]

If the guns intended role is to be shot suppressed with subsonic rounds, zero for that, and stay with that.

While you can learn you POI change when shooting the faster rounds, why bother, it will complicate your training habits.

But, if you feel you must need the extended range and ballistics of the faster rounds, then I suggest a completely seperate optic. For example, use the T-1 for suppressed close in work, for which the round was intended for, and also have a low power variable for intermidiant ranges that the faster rounds can best be utilized for. If you use a good mount, LaRue--accept no substitute, you will retain your zero with quick change abilities.

My $.02.

 

[mammynun]

the real questions is how long did you have to wait on a 10 inch blackout barrel. ive been looking for some instock for a few weeks, but im about to just get on somones list

I got mine from DSG and it was in stock at the time, took about 5 days. They seem to come and go in spurts... are you 100% sold on Noveske? Not that that's a bad thing...

 

[42769vette]

I got mine from DSG and it was in stock at the time, took about 5 days. They seem to come and go in spurts... are you 100% sold on Noveske? Not that that's a bad thing...

im 100% sold on 8-10 inch and instock ill check dgs now. to be honest i would prefer a cheaper brand than noveske

 

[mammynun]

If the guns intended role is to be shot suppressed with subsonic rounds, zero for that, and stay with that.

While you can learn you POI change when shooting the faster rounds, why bother, it will complicate your training habits.

But, if you feel you must need the extended range and ballistics of the faster rounds, then I suggest a completely seperate optic. For example, use the T-1 for suppressed close in work, for which the round was intended for, and also have a low power variable for intermidiant ranges that the faster rounds can best be utilized for. If you use a good mount, LaRue--accept no substitute, you will retain your zero with quick change abilities.

My $.02.

That's exactly what I do with this between these two:

They both wear Badger bases now (not pictured on the .223), and the Vortex is mounted in LaRue QD rings. It's painless to dial the dope between them.



I could put this on the SBR, but that makes me wish I'd got exposed turrets and I want to keep it light...

 

[mammynun]

im 100% sold on 8-10 inch and instock ill check dgs now. to be honest i would prefer a cheaper brand than noveske

Even more expensive, but it'sin stock...
Complete 300 AAC BLACKOUT Upper Receiver Assembly 9"

8" barrel in stock!!!
http://palmettostatearmory.com/inde...hf-300-blackout-1-8-twist-carbine-barrel.html

 

[JTinIN]

Well duh! I'd like to think that I'd have come up with that answer by myself, but ! I really didn't want to scope it, though I do like my 1-4x on my SPR-ish build. I also have an EoTech, but I'm don't think the 65moa/2=32.5 reticle division would be very useful for this type of application.

Thanks for saving me some ammo!

Figure would start a discussion with a list of options so everyone would have something to work off of. It often happens that everyone at the table is equally sharp and already has 7 of the 10 possible answers, but everyone has a different seven answers. Thus when one has a list of "what is known" or "the options" is easily comes down to getting all ten answers (or how ever many there are) and the one combination that actually works.

Of course the "easiest" and "correct" answer is just get as many uppers as you have loads and sight as you wish ....... insert evil grin here ;-).

Take Care
John

P.S. The Vortex scopes look nice, who did you get them from ;-)

 

[vitamink]

They seem to come and go in spurts...

Don't we all? I have never taken the time to notice that noveske's inventory is directly analogous to the velocity of my baby batter. I should pay more attention. I was hoping to order an 8.2 300blk noveske upper last week but i wasn't horny enough... i'll try again when i'm drunk.

Figure would start a discussion with a list of options so everyone would have something to work off of. It often happens that everyone at the table is equally sharp and already has 7 of the 10 possible answers, but everyone has a different seven answers. Thus when one has a list of "what is known" or "the options" is easily comes down to getting all ten answers (or how ever many there are) and the one combination that actually works.

Of course the "easiest" and "correct" answer is just get as many uppers as you have loads and sight as you wish ....... insert evil grin here ;-).

Take Care
John

P.S. The Vortex scopes look nice, who did you get them from ;-)

If it makes you feel better, it helped me out! I'm generally not that bright though.

 

[mammynun]

Don't we all? I have never taken the time to notice that noveske's inventory is directly analogous to the velocity of my baby batter. I should pay more attention. I was hoping to order an 8.2 300blk noveske upper last week but i wasn't horny enough... i'll try again when i'm drunk.

Slow down, and take note of the little things in life... Your Fiat X1/9 could use a break. And a lube job.

 

[jblomenberg16]

Tagged...I'm wondering the same thing.

Right now I'm thiking on a 25 yard zero for a 125 gr BT that will give me the following trajectories with a few of my loads:

Note that that 4MOA cone shown is +2/-2 MOA (so +/- 2" at 100yds, or +/- 4" at 200yds.)

A 25yd zero gives me a nice trajectory on my 125 Ballistic Tip (Green Line) that would be what I would use if I were to hunt with it. It would peak just shy of 1.5" between 75 and 100yds, and by 200yds would be about 4" low. That gives me a "hit" anywhere within a 4MOA red dot from pretty much point blank to 200yds.

That 147gr M80 pulldown plinker load (Red Line) has a similar trajectory and one could assume them to be pretty similar. I could zero it a bit closer (20yds), peak at just under 3" and cross over again around 150yds, and 5" low at 200yds. Again, pretty close to within a 4 MOA red dot.

The 208 subsonic (Blue) would be the tough one to get to zero, but again thinking of its useful range of <100yds, you would want to get it zerod at pretty close range.


I'll have to do some tweaking to show how each trajectory would work if they were zeroed to 25yds.

 

[MarioMarietta]

I have about 6 different zeroes for my 300blk in bolt gun 50 75 100 125 150 200 225 and yes I rained hell on a ground hog at 125 yards with some 220 grain smk fury!

 

[JTinIN]

Tagged...I'm wondering the same thing.

Right now I'm thiking on a 25 yard zero for a 125 gr BT that will give me the following trajectories with a few of my loads:

........

Nice plot, what are you using for the calculations?

Does highlight that a nice external turret scope with repeatable adjustments and possible will mil (or MOA) markings would be helpful.

 

[jblomenberg16]

Nice plot, what are you using for the calculations?

Does highlight that a nice external turret scope with repeatable adjustments and possible will mil (or MOA) markings would be helpful.

I use "PointBlank" software. It is a free ballistics calculator that has a very good datbase of powders and bullets. You basically just load in the data for your particular laoad, and the calculator estimates performance at range based on ballistic coefficient and a few other variables.

It has limited plotting capability, but does export data to a .txt file that is easily converted into MSExcel, which is what I did the plot above in.

 

[JTinIN]

Thanks will have to take a look at the Point Blank Software. Another free software for measuring group sizes and offsets (not so much for full auto but good for accurate suppressed shooting) is On Target Software.

Need to check for a shooting software thread here on INGO similar to http://www.shootguns.info/pub.htm (check a page down for software).