How much is 0.1 inch worth in fps?

[Banshee]

My new Savage 12FV shoots several loads very well. In reality so well that it complicates my development. How do you choose your load for further work when you have already surpassed your own shooting ability? I know how much movement I see in the scope and have a hard time convincing myself that there is a real difference between the groups that I can attribute to the loads.

the best accuraccy load 0.265" appears to be a medium charge of Varget, but at a leisurely 3672 fps.
The best (safe) velocity is H4895 @ 3852 fps with a group of 0.439"
The most consistent velocity is H4895 @ 3744 fps and group of 0.378"

Which to work on?

Thankfully I have stuck with one bullet Sierra 39 gr Blitzking in 204, all lengths are the same.
Varget
3573 fps, 0.268" 3 shot
3672 fps, 0.265" 3 shots
3781 fps, 0.384" 3shots

Vihtavouri N530
3776 fps, 0.386" 3 shots

Hodgdon BLC2
3734 fps, 0.462" 3 shots

Hodgdon H4895
3744 fps, 0.378" back to back 3 shot groups
3852 fps, 0.439" 3 shots

[Joe O]

You didn't say what COAL you are using.If you're using the recommended COAL from a manual,try 2.350 +/- with the varget,untill you can try IMR 8208 XBR.Other powers also work well,but 8208 is the least temperature sensative.

[hemiallen]

" I know how much movement I see in the scope and have a hard time convincing myself that there is a real difference between the groups that I can attribute to the loads."

Sounds like you need to adjust the parallax on your scope, if I understand the "movement in the scope" comment.

My son shot a 223, new to both of us but I loaded for it, and he wasn't sure why he had 2 groups, 3 ea and 2 each that were small cloverleafs about 1/2" apart. He said the scope crosshairs moved while he was shooting, so I showed him how to adjust the objective and it now shoots one small 5 shot group....


And what is your question in the title? I don't see it in the post....

If you are doing load development and can get those groups, not sure I would stop at 3 rds.... but if I had your problem I would choose the one with a powder you use in other guns, buy a 8# can and be very happy and go kill stuff....


Allen

[Fred_C_Dobbs]

If you're seeing that much movement through the scope -- if it's not parallax -- I'm going to speculate either you need a more stable shooting platform or your benchrest technique needs work. Or both.

One technique to help remove shooter influence is to shoot "round-robin," alternating loads and targets. It won't tighten your groups any but it will tend to even out the effects of aimpoint errors and barrel temperature variations so your groups' relative sizes will be a truer representation of differences between the loads.

[Banshee]

Sorry, I wasn't clear.

The movement in the scope is not parallax, it is the shooter not being able to hold the aim rock steady. For all I know the gun may put round after round into the same hole, but I don't claim to be able to aim within 0.1 inches at 100 yard and hold it there either.

I am shooting from a bipod off the tailgate of my pickup. Not supersolid, but not bad. My inclination is to take the extra 150 fps and give up 0.1 inch in group size. The reticle in my Nikon buckmaster scope covers more than the spread in the shots.

[ryutzy]

Banshee from what you said in your last post, if you arent happy with your current groups, then you need a different reticle/scope and a heavy duty rock solid rest. You are shooting good groups already. Like HemiAllen said, choose a powder that you load in another caliber and go with it. A .2 or a .4 inch group is good especially with what you are using for a rest. You average loads are shooting over 3700 fps with the 39 sbk. Like mentioned, load up and go hunt. JMO

[204_au]

Shoot 5, or even better, 10 shot groups with each load and the difference will become more obvious.

[GaCop]

+1 to what "204_au" said, three shot groups really don't show you the true accuracy of the load.

[Banshee]

I took your comments as 895good advice. Last night I loaded up three 0.2 gr steps of H4895, 5 rounds each. This morning I went to the range with near perfect conditions, 60 degrees, wind less than 6 mph, overcast skies so the chrony works well. I removed a known distraction, a 95 lb crying labrador, and left her home.

I spent a few moments leveling the bipod and added padding to my kneeling area. Fired two foulers and started.

Step 1, 27.4 gr, Pulled the first shot, knew it when the trigger broke. 3758 fps ave, 0.701 five shot group. 0.327" without the pulled shot. A good start, except the pull.

Step 2, 27.6 gr, Five good solid shots, 3827 fps ave, 0.533" group

Step 3, 27.8 gr, Five good solid shots, 3868 fps ave, 0.317" single hole group

I think I am done. Results were too good - its started me thinking I need a finer reticle and more magnification!! Any $300 suggestions?

I am shooting an out-of-the box Savage 12 FV. Haven't even adjusted the trigger pull yet.
Winchester brass, unsorted,Winchestr small rifle primers, COAL 2.35", Nikon buckmaster 4.5x14 with Nikoples reticle.

[Fred_C_Dobbs]

Banshee, increasing the number of shots in your groups isn't going to help until you can stabilize the rifle and you know all the difference is coming from the cartridge. Your aiming error compounds the bullet's ballistic error, and there's no way to tell them apart from examining the target. If you are blessed with a rifle that shoots more accurately than you can aim, you can never measure, much less exploit its full potential until you work out how to be more precise with your aiming.

The purpose of a gun rest is to increase the precision with which you select your point of aim. They do this by reducing unwanted gun movement. For benchrest shooting, the ultimate solution is a mechanical rest, known generically as a "lead sled." Some of them offer the added benefit of taking all recoil off the shooter, which can be a big plus with a punishing caliber or on a long shooting day. Some have a mechanical adjustment like a micrometer for moving the rifle's point of aim in impossibly tiny increments, and holding it there, so your adjustments can be precise to the extreme. But they can be pricey, the fancy ones are several hundred dollars.




Second best option is sand bags. Something like this for the front:



...and a smaller bag for the rear to rest the stock on. The forearm fits down inside the deep channel.

There's a variety of shapes of commercial sandbags available. If you know someone who sews, you can have one home-made out of any suitable material. The cloth feather pillows are made from works especially well. Denim can work, too. Here's an AI rifle resting on just plain sandbags:




Most commercially made bags are sold empty and you supply your own filler material. A dense filler material helps dampen rifle movement so there's no extra motion beyond what you'd intended. IMHO, sand is the ideal filler because it dampens all movements and doesn't return any energy (it isn't "bouncy"). But sand makes the bag heavy, which is why I switched to another filler. I always carry a chronograph, a spotting scope, tools and my "sand" bags in my range bag, and their weight filled with sand kept wearing out my range bags, so I switched to buckwheat hulls. Hulls are about 80% lighter than sand but don't dampen gun motion quite as well. Lead shot also is excellent filler but, obviously, is heavier still than sand.

How much stability? Even with the hull-filled "sand" bags, I know I can look up from behind the scope, then look back at the crosshairs and they will not have moves one whit. So then I only have to squeeze the trigger without disturbing my aimpoint. Off the sand bags, I find I'm able to make very fine (and repeatable) adjustments in very small fractions of a minute of angle.

Since a more stable shooting platform will help you aim with greater precision, you might have to refine your shooting technique. I don't know if you are stable enough off the bipod that you can notice the influence of your pulse through the scope but you will be off of a lead sled or sandbags, provided you're using enough magnification. When your heart beats, you will see the crosshairs shudder. Some competitive shooters actually time their shots so the trigger breaks between heartbeats so their pulse doesn't influence point of aim. Me, I can't time the trigger break with that precision.

Because all your body parts carry blood, and all your blood pulses, when I'm concerned with aiming precision in tiny fractions of a minute of angle, to my thinking, touching the gun is always bad. Always, always, always. But I have yet to figure out how to pulll the trigger without touching the rifle, so some touching is unavoidable. When I'm shooting off the sandbags, shooting for the inth degree of accuracy, I don't do a "cheek weld." There's too many vessels in your face, and too much pulse along with it. I tried not touching the stock with my cheek at all but that makes it difficult to maintain proper eye position. So I touch the stock as lightly with my cheek as possible. I call it a cheek "kiss," not a weld.

I try not touch the gun at all with my non-shooting hand. I make all my aiming adjustments by moving the rear sandbag around with that hand. I change point of aim solely by sliding the rear sandbag around. I think this is one of the keys to making very, very tiny adjustments in point of aim.

The shooter in this picture is holding his rifle just as I've described:



His rifle's forearm is resting on a small sandbag on top of a mechanical rest. His left hand is touching the rifle very little, if at all. Instead, he's gripping that brown leather sandbag you can see just a bit of under the butt of his rifle. And he's making his aiming adjustments by moving that bag.

So put your rifle on something more stable, squeeze the trigger while touching the rifle as little as possible, and I think you'll find your aiming precision will increase enough that you can easily tell which is the best load, even with just 3-shot groups.

[Trent]

Bansheee,

What is your goal with this gun?? Varmints are generally only as small as about 3 MOA. You are shooting less than 1/2 MOA.

Unless you are shooting gnats... pick your favorite powder so far and go out and enjoy your rifle!

[Banshee]

My goal is to have fun shooting prairie dogs and enjoy some load development. This gun has been a kick in the pants because it shoots almost everything well. It has been a bit of a game for me to see how small I can get the groups and get some speed behind them.

I actually have the Lead Sled shown in the picture above. I use it for shotgun load development where recoil is substantial. Also used it for my 270 WSM development. It is helpful for steadying the gun, but not a precision device. Much better for recoil reduction.

I would have been very pleased with one load that shot a consistent <0.75". I have many to choose from. H4895 and SBKs are going to do the job. Time to go into production..........

thanks for the all the help.

[Jim White]

+1 to what "204_au" said, three shot groups really don't show you the true accuracy of the load.

or inaccuracy of the load.

Can't begin to recall how many good 3-shot groups until I went to 5 and then to 10 shot groups. Also, if the load shoots good @ 100 yards try it @ 200 and see if its still good. Sometimes it isn't. Likewise, sometimes the groups are iffy @ 100/200 yards but are real hammers at 500/600 yards.

[GaCop]

+1 to what "204_au" said, three shot groups really don't show you the true accuracy of the load.

or inaccuracy of the load.

Can't begin to recall how many good 3-shot groups until I went to 5 and then to 10 shot groups. Also, if the load shoots good @ 100 yards try it @ 200 and see if its still good. Sometimes it isn't. Likewise, sometimes the groups are iffy @ 100/200 yards but are real hammers at 500/600 yards.

Good additional information. I tried the shooting off the tailgate for a short while but the crosshairs moved around too much so I ended up building a portable shooting bench with folding table legs on reinforced 3/4" plywood that fits nicely in the covered bed of my truck where it stays until I need it.

[hemiallen]

Good deal on getting successful load development.

If you are going to use the bipod for vermin shooting, your groups fired using the same equipment is great,,,, but if your goal WAS to get the best load feedback, the above suggestions on range equipment is wise to learn from for future firearms load development. You can never be too rock steady, and knowing you pulled a shot on target helps development too.


I have 3 Nikon buckmaster 6-18 SF and like them, fine dot, Nikoplex and Mil dot, and I'd swap the others to have 3 target dot scopes....


Allen