30-30 range results and question

[atr]

I loaded up 5 each 170gr RN-J, 150gr FN-J and 169gr RN-Cast
same powder charge in each....33.5 gr of 4350
I am firing at a target 100 yds out with a savage 340 bolt action 30-30

I was a little surprised at the results....the J-s hit almost at the same point which is what I was hoping for. But the Cast, hit the target about 2" lower than the J's. I was surprised, I was expecting the cast to also hit at the same spot as the J's
all the 5 shot groups were pretty good.....1-5/8"
atr

[Cree]

I’m not really surprised - barrel harmonics does weird things, and the fact the heavier boolit hit lower is likely more to do with how the boolit left the barrel than weight impacting trajectory at 100 yards. I’ve seen 168s group together an inch to the right of the same charge with 125 grainers at that range. Truth be told, those groups are likely more a statistical dispersion than anything. I’d suggest shooting two 10- or 20-round groups (with two targets) and overlay them to see where the two loads “really” group. Might even be closer (or further). Still, both of them are nice groups for the little 340. I love mine and it never fails to shoot really well with nearly any load.

Cree

[BLAHUT]

Good groups, which bullet do you prefer ?? Thats why they put those twisty tourney things on the sights...

[Winger Ed.]

That's pretty normal.

I figure the Lead boolit has less resistance than a jacketed one,
and the powder doesn't build as much pressure behind it as it runs down the barrel.
Less pressure will make the muzzle velocity slower and it'll hit lower- to one degree or another.

Either chronograph them to check. Or the redneck way to do it is fire one of each at night and compare the muzzle flash.
If the cast boolit has a larger flash, that's powder burning in front of the barrel instead of in it and generating more pressure.

It's my guess that's why jacketed powder/velocity data doesn't 100% cross over to cast.

Do a little work with powders listed as loads for cast,
and you might get the speed up and both types of ammo will hit the same.
Getting cast boolits up to full house (jacketed) .30-30 speeds is quite do-able.

[MT Gianni]

How does the bearing surface compare on your bullets? More surface contact equals more friction. In any case 2" is not enough to worry about as a plinker or hunting loads as long as you know where it shoots.

[atr]

went out today and shot another string of 5 each of the same as before....reversed the order by starting with the 169-Cast. The results were very similar to what I shot a few days ago.
then I got tired of punching paper so I set up 5 shotgun type clays and used my last 5 round of Cast...busted all clays no problem. I think the 33.5 gr /4350 is good to go for my cast and jacked.
best
atr

[Cree]

Always nice to have a load like that which just plain works no matter what projectile you’ve got to load!

[Abert Rim]

Those Savage 340s are good little guns, but don't let the secret out!

[Gobeyond]

Makes sense those two bullets would hit different on target. And two different sessions show a depth of consistency. Is the load ten percent under minimum to start? The cast almost have to be GC. Yeah not enough poop to go the distance because of lack of crimp? What about a harder crimp for the CBs. They must have had different oal . That is real different the same load for cast and j is accurate. What’s the velocity of both? It’s really remarkable. Could duplicate maybe in a 94.

What’s the question?

[atr]

I am within 95% of the maximum loading.
the crimps on the Cast are uniform, and there is good neck tension on the slug. I expected some differences in elevation. All three loads are within an acceptable (to me) degree of accuracy.
best atr

[quilbilly]

When I chronographed jacketed 160's versus the Lee RNGc's with the same load some years ago, I found that the cast were between 100 to 150 fps faster. That was the biggest difference of all the calibers I tested but in each case the CB's were coming out faster. The result for me was that I never bothered to us jacketed again in my 30/30 if I could do the same with my home grown.

[fiberoptik]

Jacketed= more friction


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