Home Forums Hunting & Shooting Ask The Gunwriters I'm Stumped.. Your Ideas

Bob,
No doubt there is a bunch card houses being built on the shaky foundation of just one pair of groups. Seeing that pattern repeat with the same load, the same everything sure would shore up some foundations.

Brent: What I'm thinking....hell I get downright suspicious if things fall together too good right off the bat..

I confirm and reconfirm over about a year before I'm firmly convinced

Looks like the 200 yds while not great, is as expected, roughly 2x the size of the 125 yd group.

I suspect the barrel has seen better days.

I love shooting mysteries like this - just not when they are with my rifles.

The problem the OP has is one that I chased for a long long time before I finally figured it out with some of my long range target rifles. I spent a lot of time and money before I figured out the problem wasn't me. It wasn't the rifle, it was the bullet.

Now I have this Marlin lever rifle that seems possessed by an entirely different sort of devil. I've got some "fixes" in the works but not much confidence that they will actually work. Time will tell, but I'm still not sure if it is the rifle, the bullet, the load or maybe even me (naw, not possible :))

Say, boilerpig, when you were shooting these two groups, did you rest the rifle at the same spot for each group? If not, that could explain the drop from 100-200 yds.

looks like a hard trigger pull ,or a flinch...

Check the action screws.
Get someone else to shoot a group.
JW

Perhaps I missed it. Once it is confirmed that the unexpected large drop is repeatable, simply remove the fore arm and shoot the rifle rested on the receiver to either indicate or rule out the fore arm as the culprit. Be advised that the POI may change with the fore arm removed though.

Brent,

You need to do more research on the science of bullet stability. I would suggest Bryan Litz's book as a starter.

One thing is certain: The two groups do not provide enough information. If we just eliminate either the left or right shot in the bottom group, the other three shots would be about as relatively accurate as the top group at 125.

The drop is more of a puzzler. Even a very bad chronograph reading (and I have seen cheap chronographs give readings as much as 10% off over the years) wouldn't explain that much drop.

The scope may also be the culprit. In fact unless a scope has really been proven on another rifle, I tend to suspect the scope first in most problems with smokeless rifles.

On Savage 99's the forend would be second on the list.

I have a 99 that does the same thing, or did. I found out I was doing a couple things it didn't like. First was it didn't like being shot off the type of rest the OP showed, or even sandbags. If I hold the forend with my hand, then put the back of my hand on either type rest it shoots tighter groups. The second thing I was doing that made it look like I had too much drop at 200 was in trying to be more precise at 200 I found I was holding the gun tighter, and worse, putting a lot of cheek pressure on the buttstock. With no cheek pressure the drop between 100 and 200 is about 2/3 that with cheek pressure.

With 99s I've always found them particular off the bench, so I always try to shoot them free recoil, with the front rest almost at the receiver (as somebody else mentioned). Don't pull them into your shoulder, don't lay on them with your cheek, don't get a death grip on the forend, and don't rest the forend on anything remotely hard.

I have Marlins and Winchesters also, that are much easier to shoot off the bench. For some reason though, the 99s always end up going hunting while the Marlins and Winchester stay home...

No, groups, esp. these do not provide enough information. But they do provide more info than you give them credit for. The biggest hint is in the biggest effect - the large drop from 125 to 200. I might know more about bullet stability than you think.

The "puzzler" fits better with my hypothesis than yours. I can't ignore, so what can explain that and, at the same time, the apparent decrease in accuracy?

Why would the scope be an issue? True, it may not be working properly, but why would it work more improperly at 200 than 125? AND why would it cause that drop?

I agree the differences in accuracy are not THAT much off from what me might expect do to just range alone but they still are more than we would expect. And I cannot "just eliminate" data without a reason either (too much like the guy that shoots subMOA all day long - except for those fliers).

And that still leaves the drop issue. I'm count that as a real issue and not some fluke of course but then that's presupposed by the entire discussion.

Stability in a 30 caliber at 1 in 10 twist is definatel not the issue


Geez

kc,

Interesting!

I tend to use softer rests than many shooters, especially with lighter rifles, and many 99's are pretty might. In fact these days I often drape a folded-up towel over the front rest, because I've found the point-of-impact from shooting over the towel duplicates the POI when shooting the same rifle over a daypack--which is how I often shoot at longer ranges in the field.

It took me a couple years to figure out how to shoot 99s off a bench. I almost sold a 250-3000 because it patterned instead of grouped; went from about 5 inches to 0.75 inches at 100 between load development and learning how to shoot it. Like my shooting mentor told me, "sometimes it's the loose nut behind the trigger"...

I forgot to mention - thanks for the towel suggestion. I'd read it in one of your posts (or articles?) some years back, and have used it successfully on other hard cases.

Brent,

Scopes can do all sorts of weird things--including erratically going from one POI to another between strings of shots. They can also start stringing shots horizontally, as in the second group. The mounts themselves may even be involved.

Your theory is based on assumptions about bullet stability that are wrong. Yes, it's coommonly believed that bullet stability declines at longer ranges, but I already outlined the reasons that isn't happening here. You just refuse to believe them, even though they've been proven over and over again.

Plus, if bullet stability were the problem, both groups would have fliers in all directions, instead of being basically strung out horizontally.

As jwp pointed out, marginal bullet stability is definitely not the problem here, and just because you've induced it with too-long bullets in your rifles doesn't change that. A 1-10 twist in a .300 Savage will stabilize a 200-grain spitzer started at 2200 fps.

Yes.

BP...

Thanks. That can be excluded.

I know you asked an important question,but my eyes keep wandering back to your avatar for some reason ,and I cant seem to remember what the hell this thread is about!!!