chicken or egg - seating depth or powder

[datsjeep]

So what comes first? If trying to develope a load and your limited to mag length do you first start with different grains of powder, find the most accurate regardless of group and start adjusting the seating depth or do you switch powders to try and find a more accurate powder.

If you know the seating depth of an accurate load i.e. factory load should you duplicate that depth, find an equally accurate powder combo then slowly extend seating depth.

It just seems with all the different factors you could shoot your barrel out before finding an accurate load.

[moombaskier]

What caliber and what bullet are you wanting to start with? Maybe I can help save you some time.

[Len Backus]

Powder first, OAL second.

[datsjeep]

270wsm in a tikka T3 150 Berger

My OAL measures 2.405 to the lands. To fit in the magazine I have to seat to max of 2.340 giving a coal of 2.895 where mag max is 2.900. This creates a jump of .065.

Most accurate load I have found so far is the factory federal premiums with an OAL of 2.238 and jump of .167 but produced 1 ragged hole at 100yds.

I have tested h1000 & rl22 at the OAL of 2.340 with poor results.

I was thinking about loading 3 rounds each of Retumbo 69-70.5 in .5 increments at the OAL of 2.240 (matching factory federal) 2.290 (half the distance) 2.340 (max mag COAL)

But I am not sure if this is a good approach.

[223Rem]

How can you find the most accurate powder without regarding the group size?

Different weight bullets work better with different powders.

The bullet design (ogive type) also plays a factor when you consider the amount of leade in the barrel's throat and wanting to keep the COAL mag length. If the barrel likes a particular bullet with a Secant ogive and only a slight jump to the lands, there is a very good chance the COAL will no long be mag length.

[datsjeep]

Originally Posted by 223Rem

How can you find the most accurate powder without regarding the group size?

Different weight bullets work better with different powders.

The bullet design (ogive type) also plays a factor when you consider the amount of leade in the barrel's throat and wanting to keep the COAL mag length. If the barrel likes a particular bullet with a Secant ogive and only a slight jump to the lands, there is a very good chance the COAL will no long be mag length.

You can't find the most accurate load without regarding group size. I don't understand what your asking.

IS it not true that a gun may appear to NOT like a bullet powder combo at 1 OAL but like that same combo at a different OAL?

[boomtube]

IF the load is no good, changing the seating won't make it so.