need some help with 77 gr SMK's

[hounddawg]

he has 0.48 moa at that distance and we expect it to grow to 0.59 moa at 300

would that be due to shooter induced error UncleNick ? That is what I attribute my groups size increases to. Thumbing, inconsistent cheek weld, gripping too firmly, scope canting, breath control and the other dozen or so other screwups I can make Then of course environmentals have more of a effect on POI as flight time increases. To shoot mid or long range well everything gear wise has to be perfect right down to the amount of sand in the front bag to how hard or soft of a hold to use.

But I agree I think he is getting about everything he can out of a off the shelf rifle

 

[Unclenick]

I agree. He's doing well with it.

The additional spread is as you speculate. In addition to individual bullets having slightly different BC's and, if you don't carefully load your bullets concentric with the case, you get more variation in initial yaw out in front of the muzzle with greater initial yaw allowing muzzle blast to exaggerate drift.

One time I had the experience of actually shooting smaller MOA at 200 than at 100. It took a while to figure out. What it turned out to be is that I used the same target at both ranges. I was able to prove to my satisfaction later (as well as hearing it from two coaches) that a smaller target makes many people hold tighter. That can make things worse if it tempts them to ambush the ten ring, but if they don't flinch, that gets them tighter groups. So at that point, I moved to shooting my air pistol at an imaginary dime-size object on the paper and it did tighten my groups some. But it will make things worse if it causes a flinch.

Another thing I've seen happen is the lower depth of field on long-range targets can cause iron sight pictures to be more difficult to line up. I used to use not only the bull but check the sides of the front sight post for equal and parallel amounts of target paper or adjacent target carrier to show. But it shouldn't matter to optical sights as long as you don't cant them.

 

[hounddawg]

your post got me to thinking of when I was first seasoning a .223 barrel. I was just doing three shot groups for chrono numbers and shot this target at 200. I chalked the .2 MOA group up to the pure outhouse luck that you can get with three shot groups but I may have to go back and revisit CFE 223 now that Varget will be scarce for a couple of months

 

[hounddawg]

Canting

was doing some practice this morning and discovered the value of anti can't devices. These groups were shot within 10 - 15 minutes of each other COnditions were identical @ 70F, sunny, 3-5 MPH wind, mild to moderate mirage from right to left. Guess which rifle has a el cheapo $14 anti cant device.

https://www.midwayusa.com/product/101958640

I was using free recoil on both groups and the 6BR shoots nice round .5 MOA groups at 100. I will be putting one of these little bubble levels on every target rifle I own

 

[rebs]

I do have more horizontal spread than vertical spread. Groups are kind of like egg shape. I just measured a few groups I shot at 100 yds and they measure 0.254 on average center to center. I will run velocity tests as soon as I get a warmer day maybe in the 50's, right now has only been in the low 40's.

 

[hounddawg]

post some pics of these groups , a lot easier to analyze that way

 

[Unclenick]

egg-shaped at 100 says to me you still aren't quite on a sweet spot. It's not uncommon, as you step through a ladder, to see the groups move from egg-shaped left-to-right to round to egg-shaped top to bottom. If they don't do that, though, and stay left-to-right egg-shaped, make sure the gun isn't able to slip sideways in recoil. I find they do for me in prone position, slipping off my shoulder to my shoulder toward the outside. With .30 cal service rifle I always have to crank in 2 MOA of right windage to compensate for the butt jarring elastically to my right and the muzzle to the left (I am right-handed and right-eye dominant). It's about 1 moa with the AR platform. It's very consistent and simply how I am shaped, I suppose.


Hounddawg,

Nice shooting. How much difference are you crediting to the anti-cant level?

 

[rebs]

I talked to a guy at our club who is a fantastic shooter and he asked me if I might be letting the rifle cant or move when I squeeze the trigger. He suggested I try dry firing with a coin placed on the top of the barrel and see if the gun moves and the coin falls off the barrel. He also suggested keeping my eye in the scope after the shot and see where the cross hairs are on the target.
He figured my load was good and I was influencing the groups because my groups are great at 100 yds but not so good at 300 yds as any slight error on my part would definitely influence the results on the target at 300 yds much more so than at 100 yds. My groups at 100 yds are all shots touching, they are only egg shaped at 300 yds. I could have a problem similar to Uncle Nick but in a different way.

Is there a correct way to dry fire a center fire rifle ?

 

[Unclenick]

Most will tolerate dry firing just fine. The AMU coaches encouraged doing a lot of it as the military-style guns definitely handle it. If you have any doubts, you can get a snap cap type dummy in your chambering.

 

[hounddawg]

my groups are great at 100 yds but not so good at 300 yds as any slight error on my part would definitely influence the results on the target at 300 yds much more so than at 100 yds.

exactly the way I see it

That is why it is such a challenge. A buddy I was shooting with the other day said he set a goal when he retired that he would be able to hit a dozen eggs at 300 yards with 12 shots. He said that was 10 years ago and his goal now is to be about to hit a dozen eggs at 300 yards with 12 shots.

I think you are discovering what I discovered a year or so back. Verticals are easier to tame than horizontals. On that target above Both of my verticals are less than a third MOA but the horizontal on the 6BR group was horrible. It wasn't the rifle or the ammo it was me, 100%. I tried the same hold technique I use on my wider forend rifle and the rifle was canting and twisting when fired.

Here's a suggestion. Next time at the range use a small tripod and your phone and video tape yourself when shooting. Then replay it and wath yourself, it's even better if you can buy/borrow a target cam and watch yourself and the rifle to see what caused that flyer

Anyway I think you heading down the rabbit hole, have you started buying books by Lentz and Boyer yet and watching every LR shooting video on the net? Might as well start saving for that custom rifle and $4K scope now. It is only a matter of time

 

[rebs]

I am determined to lick this problem with the rifle and scope that I have. Will power and determination and education from all you guys.
Thank you all you guys for all the great help.

 

[hounddawg]

there is a million and one videos out there that will help also

edit - buy this, put it in the john then read it till the covers fall off. I have shrank my long range groups by 2/3rds in a year with a lot of practice. Take any decent .22 LR and shoot lots of rounds at 200 yards over simple wind flags. You will be amazed at how fast you start to pick up wind skills

https://www.amazon.com/Wind-Book-Rifle-Shooters/dp/1581605323

I bet you can get that Tikka down to .3 MOA at 300 with practice

 

[stagpanther]

edit - buy this, put it in the john then read it till the covers fall off.

Reading about it while passing it? Looks like a good book, I'll check if I can get it for kindle.

I found it and clicked on ordering it--and it was only after ordering the kindle version that I noticed it was a "pre-order" and won't be available til March 2020.

 

[rebs]

It is snowing here right now so my trips to the rifle range could be slightly limited, but I will be doing lots of 22 rifle shooting indoors to work on my shooting skills.

 

[hounddawg]

any practice is better than no practice for sure Rebs, In my next house I want a unfinished basement where I can set up a 15 meter air rifle range.

In post 10 the 5 shot 6BR group I shot was all strung out left to right but the 6CM group shot was round and tight. I determined that rifle cant and twist was what was causing the stringing. The problem was the front bag was too wide for the 6BRs stock, it was made for a wider fore end like the one on the 6CM rifle. I bought a second front bag the proper size and got a 15 shot group today with a 4.2 inch width and a 4.3 inch height at 600. Just goes to illustrate how much difference a proper front bag can make. Too loose on the sides and the rifle will twist but you don't want it too firm either, that will cause a different problem

 

[rebs]

A friend loaned me a Sinclair concentricity gauge to measure my case neck run out and my 223 LC cases are out by 2 thousand at the most. That should be good to go right ?

 

[Unclenick]

I'll second on that book. I got it a number of years ago and felt it was a good read. Jim Owens' books, Reading the Wind and Coaching Techniques, and Sight Alignment, Trigger Control and the Big Lie, are practical for match shooters and cover his approach to adjusting sights for wind without getting yourself caught up in "chasing the spotter".

 

[hounddawg]

thanks for the recommendation Nick, got both on my kindle now

 

[Road_Clam]

Just because you observe .5 moa at 100 yds does not mean you will yield .5 moa at 300 yds. My proven high power competiton load is the 77 smk with 24.0 gr of Varget. With my AR15's 20" , 1-7" twist White Oak barrel im going to call it a consistient .8 moa at 100 yds. When i shoot the same exact load at 300 yds ill typiclly observe about 1.4 moa. Shooting this load at 600 yds is about 2.2 moa. I prefer using the 80 gr SMK bullet at 600 as it bucks the wind a bit better.

 

[rebs]

Just because you observe .5 moa at 100 yds does not mean you will yield .5 moa at 300 yds. My proven high power competiton load is the 77 smk with 24.0 gr of Varget. With my AR15's 20" , 1-7" twist White Oak barrel im going to call it a consistient .8 moa at 100 yds. When i shoot the same exact load at 300 yds ill typiclly observe about 1.4 moa. Shooting this load at 600 yds is about 2.2 moa. I prefer using the 80 gr SMK bullet at 600 as it bucks the wind a bit better.

are you using Varget for the 80 SMK's also ?