Bullet weight and ballistics

[Caldart]

I purchased a TC Encore Katahdin 45-70 and started reloading. Before I reloaded my first rounds I purchased some Federal and Winchester 300 gr hollow points and some Hornady 325 gr FTX to get the rifle semi zeroed in on paper. It has peep sights and all rounds were verticle +/- 3" @ 50 yards with the peep sight ramp in the middle of adjustment.

Well I decided I wanted to shoot some cast 405 gr FP and loaded them up with 29 gr of IMR 4198. I took them to the range and found them shooting 15" high with the peep ramp bottomed out. I went out and picked up a box HSM Cowboy Action 405 gr rounds and they shoot the same, 15" high.

Couple of questions I have since I'm new to reloading and the 45-70 itself. Is there that big of a ballistic difference due to the bullet weight? I would have thought the heavier bullet would have hit low compared to the faster lighter bullet. Is it the gun just doesn't like that weight bullet?

Looking for any info/input while trying to learn about this new hobby. Thanks for any help.

 

[brewer12345]

I find cast to often shoot higher than jacketed loads. I theorize that it may have something to do with the lower friction of cast compared to jacketed, but who knows.

 

[Schwing]

Part of this is due to the fact that the heavier bullet is, most likely, moving slower. It takes longer to travel down the barrel and the barrel is rising the moment the powder is igniting.

 

[Caldart]

Part of this is due to the fact that the heavier bullet is, most likely, moving slower. It takes longer to travel down the barrel and the barrel is rising the moment the powder is igniting.

It's a really light rifle. I'll bring a lead sled out and see if it makes any meaningful change to the POI.