[marsms]

I've got a questions for you kings of reloading. I took my CZ 527 FS out today, to test my Nosler 50 gr. Ballistic Tips loaded with IMR 4198. I worked my way up with single shots to check for pressure, and when I hit 20.7 grains (my first group), I was impressed.

I should also tell you guys about how I'm a bit on the weird side (apparently). I always shoot 4 shot groups. I then cancel out the farthest shot, and call it operator error, wind, flinch, whatever. That way I'm always left with a three shot group.

So, I went round robin. The three groups of particular interest were shot with 20.7, 20.9, and 21.1 grains. So I fired one round of each charge (allowing two minutes between shots, as I've always done), and started on the next round. With the 20.7 grain charge, I landed my second shot 1/4" away (to the left) from the first. I was happy with that. The 20.9 grain charge ended up about 3/8" away from the first, and the 21.1 grain charge ended up nearly an inch away from the first. Fine.

On to the third round. My 20.7 grain charge landed the third shot 1 1/2" away (lower) from the first and second. I kind of assumed it was my fault, but didn't think it should have been. The other two ended up in pretty much the same way.

The fourth round put my 20.7 grain charge within a 1/4" (to the right) of the previous shot. The 20.9 and 21.1 charges did the same thing, except they ended up about 1" to the right of the previous shot.

It was -9 degrees Celcius, only a very light breeze. Nothing changed (that I'm aware of) between the second and third rounds to make them drop 1 1/2" lower. I went on to shoot a coyote at about 280 yards with factory ammo (which it was sighted in for) later on towards evening, and the bullet ended up right where it should have, so it can't be the scope. Do any of you folks have any ideas?

 

[broom_jm]

Would it be possible to post a picture? I'm trying to understand if you're firing a single group with different charge weights...I can't quite grasp what you're asking, here.

 

[EWestbrook]

I'm not sure of your question either. What size are the groups? Your best group? I've never tried the round robin method but have studied with interest.
I have recently found a good combo with my .222 and am now studying about a load for my .223.

 

[marsms]

Nope, sorry guys. Firing three groups with three different charges. First fire one at one charge (say, 21.7 grains), then fire one at a different target of your next charge (21.9 grains), and then a third shot at a third target (22.1 grains). The you start back at the beginning with the first target and the 21.7 charge. That way all three charges and all three loads are subject to essentially the same conditions. This, rather than firing three rounds of one charge, and then three rounds of the second charge, and by the time you get to the last one, the wind is 5 mph stronger . This way every charge is subject to the 5 mph wind when it comes up.

My best group came in at about 1 1/2", whereas the worst came in at about 3 1/4".

 

[broom_jm]

Nope, sorry guys. Firing three groups with three different charges. First fire one at one charge (say, 21.7 grains), then fire one at a different target of your next charge (21.9 grains), and then a third shot at a third target (22.1 grains). The you start back at the beginning with the first target and the 21.7 charge. That way all three charges and all three loads are subject to essentially the same conditions. This, rather than firing three rounds of one charge, and then three rounds of the second charge, and by the time you get to the last one, the wind is 5 mph stronger . This way every charge is subject to the 5 mph wind when it comes up.

My best group came in at about 1 1/2", whereas the worst came in at about 3 1/4".

OK, now I get what you're saying. I think this is the method Uncle Nick has referred to a couple of times, and it sounds interesting! However, those group sizes can't be very inspiring to you, huh?

Was your best group with a near-max charge? This may be flawed logic, but when I work up my own handloads I do the following and if the results are not great, I change powders:

1) Seat good quality bullets ~.020" off the lands.
2) Work up in .2/gr increments (as you've done)
3) Clean and cool barrel between every group
4) Use a very sturdy rest to take the "shooter" out of the equation, as much as possible

(I use a Lead Sled, weighted down with 20lbs of shot, and adjust the rest so that when I shoot, only my thumb and trigger finger are touching the gun, with equal pressure applied by both. This is how an old bench-rest shooter taught me to do it and I've always been happy with the results.)

When working up a load I am used to seeing the groups be a little spread out with the starting charge, getting tighter as I get close to a maximum charge, with the best accuracy either at, or slightly below, maximum. Again, if I don't see this pattern, I try a different powder. I have not found a bottle-necked cartridge yet that won't show this pattern, when I figure out the right powder for it.

P.S. When I find a powder that shows the above pattern, I work with the best charge weight and adjust seating depth to see if I can improve on the groups that way...kind of like the super-fine adjustment knob on a microscope.

 

[marsms]

No, they're not particularly inspiring at all.

My best accuracy has been comming from slower charges (though I have yet to get up to maximum with either IMR 4198 or H-Varget). Actually, with the Varget I managed one group where all three shots ended up centered right on the same vertical line...only problem was that they were each 1" apart, giving me a 3" group.

So, I guess my question really is this. What am I doing wrong that I'm getting so much vertical spread in my groups, even though horizontal spread is very minimal?

Edit- I've been using a BullsBag and the set trigger on my CZ. I put my scope on 40X, and at 100 yards the intersection of my crosshairs never leaves the 1/2" gradient on my targets, so 1/2" spread is really the top end of human error. Granted, 1/2" is a fair bit more than none, but it's seldom that a round leaves the barrel when the crosshair are 1/2" off the zero on my targets as well.

 

[Rocky Raab]

I'm going to take a stab at either bedding or poor barrel harmonics. If the rifle has a bedding issue, groups will be large and can wander - much as you've described, I think.

Poor harmonics means the barrel is pointing in odd directions as it vibrates during the shot (all barrels do). One shot the bullet leaves with the barrel pointing high, the next one low, the following one left, etc.

 

[marsms]

If it were a bedding issue, I'd likely be seeing the same things when shooting factory ammo, correct? Because my factory ammo groups quite consistently...the groups are usually around 1 1/4", depending on specific bullet selection, and whatnot, but they are always neat little triangles.

If the barrel harmonics are a problem, might there be a chance of improvement with any given load, or do you think I'd likely see roughly the same pattern all the way through?

 

[EWestbrook]

As the powder charge changes, so does the harmonics. Sure, if the bedding were an issue it should show up with anything fired. Keep working with your reloads and change only one thing at a time. I'm having a hard time working up a load that gets the accuracy with my .223 and factory Hornady ammo. Once you have tried many variables with one powder, move to another and repeat. It has helped my shooting in general with the practice anyway.

 

[MikeG]

Assume you are making sure the bullets are seated straight. That can do funny things to groups.

Also, one difference with factory ammo is that it is crimped. More bullet pull, which also affects the barrel time as well as consistency of powder burn.

Just a few thoughts.

 

[marsms]

Well, I mean...I don't have a concentricity gauge. When I seat my bullets (Lee's Dead Length Seater) I give them a half turn, to hopefully help straighten things up a bit.

 

[MikeG]

Roll them across a smooth tabletop to check.

 

[marsms]

They look pretty darn good to my eyes!

Wait, let me rephrase this...they look perfect to my eyes.

 

[Rocky Raab]

Many here would say that your factory groups (1 1/4") aren't that stellar. That's what prompted my bedding comment.

No aspersions intended, but first have somebody else shoot the rifle with a known load (factory, probably) and see if things improve - or not. The shooter is one of the easier variables to isolate - and again that is not a slam. Technique does matter off the bench.

 

[marsms]

No no, I absolutely agree. Just FWIW, I can get about 5/8" groups with my completely factory .270 WSM Model 70 Featherweight (that is, using factory Winchester ammunition). I really don't think I'm the problem, because as I said, my crosshairs never leave the 1/2" gradient on my targets.

I didn't mean that my factory loads are shooting WELL, really...just that they group around one point. My reloads are tending to string out vertically, though often the are nearly dead on horizontally.

Nevertheless, I agree there is always a chance it could be my fault...I'll have to get one of my younger cousins to give it a shot and see what they come up with.

 

[marsms]

I really wish I had some way to show you folks this target, so you could see just what I mean. Essentially, for my 20.7 grains group (the one that seems to show the most promise so far), ended up like this:

..
..

The one with the most consistent horizontal grouping with the Varget ended up like this:

.
.
.
.


I don't know, but hopefully that will help some of you visual folks?

 

[broom_jm]

I really wish I had some way to show you folks this target, so you could see just what I mean. Essentially, for my 20.7 grains group (the one that seems to show the most promise so far), ended up like this:

..
..

The one with the most consistent horizontal grouping with the Varget ended up like this:

.
.
.
.


I don't know, but hopefully that will help some of you visual folks?

Actually, that helps quite a bit.

I am nowhere near as experienced as Rocky, but when using the loading technique described earlier, my groups tend to string vertically, until I get to the right powder charge, where they tighten up. You can actually see that in the pictures of the groups I am getting from the 358GNR. I will agree with you and Rocky that if 1.25" is the best you're getting from factory ammo there may be something else that needs to be resolved, aside from what you're doing at the loading bench.

 

[Rocky Raab]

Oh pshaw, broom. I'm no eggs spurt, just some phardt with 50+ years of trigger yanking and press handle pulling behind him. I could probably learn a thing or three from most folks here - and would be delighted to!

 

[MZ5]

It could be that you're simply not near the OCW. (Isn't that the method you're using? Your description matches that method exactly.) If your best groups are the lightest of the 3 charges you tried, then I'd suggest loading that charge again and going down a couple increments as well. Or, you can go up and look for the next node.

Alternatively, fiddle with seating depth, but I'd try more charges first. I mean, you've only tried 3 charges so far! Another thing you can try if you can't get anything to tighten up is to not use the set trigger. I won't claim that mine shoots better or worse using the set trigger, but it most definitely shoots differently using set vs. standard. Different POI and different grouping.

 

[marsms]

It could be that you're simply not near the OCW. (Isn't that the method you're using? Your description matches that method exactly.) If your best groups are the lightest of the 3 charges you tried, then I'd suggest loading that charge again and going down a couple increments as well. Or, you can go up and look for the next node.

Alternatively, fiddle with seating depth, but I'd try more charges first. I mean, you've only tried 3 charges so far! Another thing you can try if you can't get anything to tighten up is to not use the set trigger. I won't claim that mine shoots better or worse using the set trigger, but it most definitely shoots differently using set vs. standard. Different POI and different grouping.

I suppose I am using the OCW method, just...not intentionally. Really all I'm doing is old fashioned, plain jane round robin. I think the OCW method differs from the round robin method (essentially) in the way the target is read? I'm planning on going up from where I'm at, and hopefully this stuff will be resolved, but I am curious about what's going on here...these two powders are my first experiences with reloading, so if there's something I can take away from it, I'd sure like to! I'm not willing to go down from where I'm at (not from my lighter charges anyway). If I'd have to go down from there I'd just as soon use factory ammo.

As for the set trigger, I don't know...I shoot groups both ways with factory ammo, and honestly, I don't notice much (if any) difference in either point of impact or grouping. I just like being able to touch it off, because it makes it a lot harder for me to accidently jerk the trigger.

Thanks for the advice guys, and I guess I've got some stuff to try out now...