300wm help

[themayor]

I have the sinclair overall length tool. When trying to figure out my overall length i come up with 3.5275 with the sinclair unit. When i load a shell up that size it is alittle tight but will close and when i take it out the reading is 3.4945 which puts me off .033 from my first mesurment. What one should i go off of and when i do get my overall length how much should i back off the lands.

 

[billmo]

Well, the loaded round would be my choice. I'd start there with a reduced load and work up til I found something that looked promising and then play with seating depth til I was happy. Just my opinion. Bill

 

[themayor]

Should i start with it tight and work out if need be or start lose and work my way in?

 

[britz]

I generally start a couple thousandths short of hitting the rifleing and work my way back if I can - most of the rifles I load for have such bad freebore that I can't get that close to the rifling.
Billmo is right when he says to start at the shorter of the two because apparently your rifling is pushing the bullet back into the case slightly. He is also right in starting with a reduced load because the pressure can build up when seating so close to the rifleing.

I think I'd start tight to the rifleing and work the load up as much as I safely could. If I wasn't happy w/ the accuracy and the speed, then back it off a few thou and do it again.
Just my $.02

 

[themayor]

OK so start back maybee .003? And the load i am using is near book max so would it be ok to stay with it? 73grains of reloader22

 

[billmo]

Nope. You want to jam to lands and back off of that max. load by a couple of grains or so and work your way up maybe .5 gr. per jump til you see pressure. Bill

 

[themayor]

ok so you are saying leave it tight to the measurement i got when i closed the round the camber and back off my charge alittle

 

[billmo]

Yes Sir. That is correct. Bill

 

[themayor]

OK thanks does starting a 70 sound like a good starting point or is that still alittle to high?

 

[billmo]

Yea, 70 would be O K if 73 is the top load with that powder. Bill