.243 seating depth

[Ballie]

Guys, I have started working out a load for my new Sako varmint .243 with a 70g Nosler BT it seems to like 41g of varget, I am now making up some rounds all at 41g varget but with different seating depths.

 

My question is the lands are at 2.325 (with Hornady oal gauge measured from the ogive) but if I set a bullet 10 thou off ie at 2.315 there is only 4mm of the bullet in the case, however there is only 3mm in reality being griped by the case because of the boat tail bullet.

 

Is it ok to load with only 3 - 4mm of bullet in the case? I know poeple say you should have the bore diametre in the case ie 6mm but this would put me 75 thou off the lands, I have loaded some 10 thou off (2.315) and checked the run-out and it is only 2 - 3 thou.

 

But I have not shot them yet.

[AndyCM]

Ballie,

 

I'd stuff then in a bit more if I were you, they will probably shoot like **** and possibly be dangerous.

 

The rule I go by is in by the diameter at least - 6mm in this case.

 

Might be 60-80' off the lands but they won't fall out in the field.

 

Q, a pro to get the technical version of the above B)

 

Cheers

 

AndyCM

[Dunkield]

This won't answer your question Ballie but have you tried shooting them way back off the lands?

Not all guns like the head up close, my Tikka shoots Federal factory ammo really well even though they are 200 thou off B)

[wy111]

Using the same ammo and powder(41.5gns though) and 40 thou off lands, gives me a seating depth of .684. Speed averages 3553 fps and and usually under .5" moa at 100yds. Crimping is not usually advised or neccesary for bolt actions, only for tubular magazines and self loading rifles.

[v-max]

Hello the OAL gauge is only a rough guide to your depth & not accutare unless out of a case shot in your rifle.I have found this out & had it confirmed on another site from more people in the know.I have ended up back to a case with a split neck & cut it with wee dremil type thing & get seating depth this way again.Best to try some diffrent depth's as i have the same prob as you in both 22.250 & 25/06 but shoot well for me in a hunting round.

[Ballie]

Well its all sorted now, I have settled on 41g varget/70g nosler BT/fed 210 match and 55 thou off lands was best, here is a group of 4 bullets shot at 200 yards.

 

[kip270]

I would say so Ballie B)

[markbivvy]

Sorry for dragging this back up but,

what happens if you seat the bullet at say 50 thou back from the lands and it take you under the bullet minimum lenght.

please.

Edited August 30, 2009 by markbivvy

[DaveK]

Sorry for dragging this back up but,

what happens if you seat the bullet at say 50 thou back from the lands and it take you under the bullet minimum lenght.

please.

 

Just let it out a bit then mark. Or if it works, leave it.

 

Gents, being as it's Nosler BT's under discussion were not talking about punching same hole groups in paper so why the quest for the perfect shot? Sorry to be so anal but you're kill zone on larger quarry doesn't warrant it.

[markbivvy]

Just let it out a bit then mark. Or if it works, leave it.

Thanks Dave. man.

[weejohn]

Sorry for dragging this back up but,

what happens if you seat the bullet at say 50 thou back from the lands and it take you under the bullet minimum lenght.

please.

 

i say if it works load them up and shoot them but remember the pressure is increased the further you seat the bullets into the case. I get .215 moa accuracy at 100yds with the bullets seated .015 under recommended case length but also get single holes at 100yds with the bullet seated only .150 into the case, these are with 65gr vmax in the 243.