I'm thinking way too much I think!

[Ksmirk]

Ok I think I let my mind get the best of me here and now I'm doubting myself! I've got some new brass and if my math is correct there is around .007" that the shoulder is going to have to move forward to form to the chamber so I'd like to soft seat the bullets into the lands so the base of the round is held against the bolt face..... it's been 15-20 years since I've done this but is backing off 10% from max load sound about right?

GO gauge bolt drops easy but Scotch tape on the end I get some resistance at the bottom of the bolt throw and measuring brass with a comparator is right at .007" short taking the shoulder datum from the reamer print plus .002" for the tape, am I putting too much thought into this? sorry for the bother fella's!

Kirk

 

[SKWERLZ]

False shoulder is an even better method of holding the case against the boltface face.
I always shoot a moderate load in the first firing of brass.

 

[ronemus]

You'll need to hard seat into the lands to keep the firing pin strike from driving the case forward.

 

[K22]

If you F/L size to "0" bump, won't the cases eventually form? At least that's what I do with virgin cases. I measure the fired case head space of about 5 or 6 cases after the first firing and set my die to F/L the longest case to "0" bump. The others eventually catch up or extrude up to that amount eventually having all cases with relatively the same case head space.

This way I am not over working the cases. As I have often said on other posts, in my experience, it is the radial dimension that is often the culprit creating hard chambering. This is why I prefer F/L to "0" zero bump over neck sizing. I can often go 10 sizing without having to bump the shoulder using this method.

Also, I am not wasting components or time trying to fit the cases to the chamber. I am performance shooting from day one with virgin cases. I have even quite successfully hunted varmints and predator with virgin cases.

PS: I am not a competitive shooter so take what I say in that vein.

 

[L.Sherm]

Just run a middle of road load the first time and you will be fine, .007 is not the end of the world. Ive had as much as .010 on belted mag brass

 

[Ksmirk]

You'll need to hard seat into the lands to keep the firing pin strike from driving the case forward.

What is your hard seat depth? this is a process I don't do much at all reason I ask, just trying to get this brass done with barrel break in, it'll be a hunting rifle so not a lot of rounds will go down the barrel.

 

[L.Sherm]

What is your hard seat depth? this is a process I don't do much at all reason I ask, just trying to get this brass done with barrel break in, it'll be a hunting rifle so not a lot of rounds will go down the barrel.

Watch Alex Wheeler method or im sure theres others on youtube. any of them will work for what your doing.
Your " hard" seating depth is gonna depend on the reamer freebore that was used.

 

[Coyotefurharvester]

I just seat a spent primer 0.010 proud in new brass and chamber it, remeasure(overall length). Than you know how much the shoulder needs to move. Do 5 cases and average it.

 

[Fast14riot]

To answer your question, yes your math is correct. New brass is often that short or more at the shoulder, so it will chamber in any rifle on the market.

Moderate loads for first firing seem to make brass last longer by not overworking it at once. I bet it'll fire just fine as is without a false shoulder or seating jammed, however you may get greater variation in base-to-shoulder dimension of 1x fired brass than using the aforementioned methods.

 

[6BRA]

Alpha?

 

[Ksmirk]

Alpha?

Peterson

 

[Ksmirk]

To answer your question, yes your math is correct. New brass is often that short or more at the shoulder, so it will chamber in any rifle on the market.

Moderate loads for first firing seem to make brass last longer by not overworking it at once. I bet it'll fire just fine as is without a false shoulder or seating jammed, however you may get greater variation in base-to-shoulder dimension of 1x fired brass than using the aforementioned methods.

I'm too OCD and I like repeatable so why I reload I've no idea lol but the results after a mess of frustration when they go right sure is worth it. I can just anneal after each firing to ease the brass so it's not too overworked BUT you're probably correct in that it'll fire off just fine but it sure would be nice to get nice formed brass first time out..... components aren't cheap like they were 5 years ago!

Kirk

 

[J_idaho]

Why not start doing seating depth testing instead of wasting all those rounds on one seating depth.

 

[L.Sherm]

Why not start doing seating depth testing instead of wasting all those rounds on jamming the lands.

Sometimes jamming the lands is not a waste, depends on how far.
Theres only one way to find out, shoot it!

 

[Ksmirk]

Why not start doing seating depth testing instead of wasting all those rounds on one seating depth.

If you seat a bullet .010" off the lands and the brass is .007" shorter than it should be how far off the lands would that bullet be when the firing pin hits the primer..... the brass will travel forward until the powder goes off forming the brass to the chamber so the reason I don't just start bullet seating now is the results will change from a virgin case to a fired case.

 

[Ksmirk]

Sometimes jamming the lands is not a waste, depends on how far.
Theres only one way to find out, shoot it!

Kinda where I'm at, my OAL is .050" over and can still fit the magazine so I'm just going to drop the powder charge 2gr stick the bullet about .015" in the lands and torch em' off. I've got some powder that's been sitting around awhile I don't normally up may as well burn it up and found a box of bullets a buddy brought over when I re-barreled his rifle.

 

[JEFFPPC]

How to make something simple hard,lol. Make a dummy round so your bullet engraved for the lands .010 to .020, it's not real critical load up your rounds with a powder of the faster side a little below max and shoot them......good to go.....simple. I've done that with thousands of cases in dozens of barrels for 60 years with excellent results. Never forget the KISS method and don't worry about sounding smart.

 

[Webster]

What is your hard seat depth? this is a process I don't do much at all reason I ask, just trying to get this brass done with barrel break in, it'll be a hunting rifle so not a lot of rounds will go down the barrel.

Funny factory ammo fits the chamber very sloppy. Billions of rounds have been fired without jamming into the lands. With my 6BR with new brass I fire a normal load with just touch. My 6BRX when FF I load my normal 6BR load and just touch. Never had a problem. Maybe when the round goes off the bullet gets pushed into the lands and the case gets pushed backwards. Force always in both directions. I would think the chamber pressure would over come the FP force and pressure pushes in both directions. Who knows?

Added later:
Vamint Al calculated that when the bullet enters the lands the chamber pressure is about 8000 PSI.