Ask the hexperts

[gunnut14]

I went to the range yesterday. Went to shoot a couple of my new rebuilds.
A couple of Chech Mauser/Isralli Mausers in .308
I bought them as "U Fixems " from CIA arms for the receivers and bolts.
Both bores were well"OK" but noting to write home about.
New wood in Manlicher style.

With 30 grains of IMR 4895 I shot low and to the left.
About a 2 inch group with 8 rounds. at 100 yards ( steel plate)
OK i said move the front sight a little when I get home and should be great

Same gun same day ,(have not moved the sights yet.
14.5 grains of unique shoots low and to the right.
Again about a 2 inch group at 100 yards , (steel plate)

Temps about the same. no wind to speak of.
Barrel temps same as I let it rest before changing powders

All said I need a little guidance on what to do.
Am uping the unique to 15 grains and will check it next range day but could use any ideas as the old warhorse is really a fairly good shooter.

Forgot the boolit was a lee C308-160-F both time , Gas check and lube the same.

gunnut14

[Bloodman14]

What exactly is it you want to do? I am not following.

[303Guy]

Sounds like a lot more load testing is required before a change to the sighting is made. See if you can get the POI to swing from one extreme to the other if you can. Perhaps just finding 'the load' before making any sighting adjustments.

By the way, with my eyes, I find the angle of the sun on those V sights can cause me to shoot one side or the other.

How is the bedding/fore-end contact/pressure on the barrel? The lighter load would be less influenced by barrel contact.

[gunnut14]

Gunnard,
I was hoping to get some idea as to why one would give me lower right the other lower left. with out any sight changes!

303Guy,
I have spent a day loading a bunch of shells with various loads to do that very thing.
personally I think maybe the unique even tho it doesn't have the oomph of the 4895 is a better powder for the load and lee boolit.
Time will tell!


gunnut14

[Billwnr]

It's different barrel harmonics because of different powder loads.

[303Guy]

Agreed. The question I ask is why so much? But the difference between is 30 grains of 4895 and 14.5 grains of unique is actually quite a lot in terms of barrel harmonics. Especially if the harmonics are being affected by barrel bedding in the fore-end.

[Bret4207]

It's different barrel harmonics because of different powder loads.

And recoil impulse is different. The torque differs, maybe barrel time too and harmonics. Kinda like why Winchester 180's in your '06 hit in one spot and Remington in another and Federal in a third.