Seating depth question

[Captain Skip]

Just loading my first batch of 170 gr powder coated bullets for my 30-30. I have the die adjusted so it’s currently seating at 2.545, spec is 2.55 so it’s a RCH under OAL spec. But, should I set a bit deeper to make sure the crimp goes into the groove? See photo - I put a second bullet alongside for comparison. Don’t worry about the black on the case, it was a throwaway that I am using to set the seating depth.

[popper]

Don't worry about OAL spec! Seat to what fits your rifle, not jam lands, and cycles from the mag/tube. Lee FCD for crimp where ever that is. OAL, twist, barrel length are test specs for the test gun. Pressures are from the test gun. I use mid load jacketed data, my OAL and go from there. It will be safe. There is no problem using the crimp groove, just might not get the best performance/accuracy.

[charlie b]

Simple. Depends on your chamber and throat. If the cartridge cannot be chambered then it needs to be shorter. Henry rifle that I have loaded for had a really short throat so bullets needed to be deeper. Win94 had a longer throat.

If it can be chambered then the question is 1) crimp or not, 2) crimp in groove or not. For roll crimp and revolvers I crimp in a groove. For rifles I use the Lee collet die so I just crimp it wherever I am at with OAL (if I crimp at all).

[stubshaft]

It depends on how tightly the neck grasps the bullet and if you are going to be loading them in the magazine. Seating a little deeper is NOT going to cause you any problems.

[Bazoo]

I would start by seating to the crimp groove. If you are using a roll crimp you need to crimp there. If a lee collect crimp die, then it doesn’t matter. But my guess is you will likely need to seat deeper so you don’t jam into the rifling. The reason I’d start with seating to the crimp groove is that it’s the norm for caliber and will give you a base as you begin to figure out what the gun likes.

[Winger Ed.]

If you're doing the roll crimp, I'd seat, then do the crimp as a separate step, on the crimp groove.

If you want a quick way to see how far up in there the rifling is, do a little bit of neck sizing on a case so you can
move the boolit in it with thumb pressure. Chamber it and let the gun push the boolit back.
Pull it out and you'll see how deep the chamber really is, and how long of a OAL you can potentially have.
If it pulls the boolit out of the case, tap/push it back out and give the case a little bit more neck sizing.

[archeryrob]

That big flat nose probably needs to be seat shorter than an OAL for a typical spire point bullet. The skinny tips go farther up the barrel. I get a empty case seat a bullet and chamber it, keep pushing it down until it fits. Then you know the OAL you need.

It varies per rifle too. My old waffle top 1958 30-30 and I made rounds for it to match it. 2 buddie shave newer micro groove marlin 30-30 and the OAl for mine will not chamber in their guns and they cannot lclose the action.

[Hick]

All the right advice above. You didn't say what kind of rifle you are using. If its a lever (like mine) you don't necessarily need a crimp-- provided you have good neck tension. That is, if you can push the cartridge against your bench with a few pounds pressure without the bullet sliding into the case then a crimp isn't usually needed. You need enough neck tension to resist the pressure from the magazine spring with a little extra for recoil. You don't need a lot, because in recoil the force on the cases is limited by the spring force (higher recoil just lets the cases move against the spring). This gives you more flexibility for seating where it best fits your chamber.

[Captain Skip]

Thanks all. I’m loading these for a Marlin 336 microgroove. I ended up seating deeper. I tried loaded the dummy test round and it was very difficult to close the action. It also left the start of rifling marks on the bullet. So I set a little deeper and tried again. It took about 4 tries but I got the length to where the lever closed properly. Ended up with an OAL of 2.45. The crimp is just a hair above the top groove.

[Bazoo]

Thanks all. I’m loading these for a Marlin 336 microgroove. I ended up seating deeper. I tried loaded the dummy test round and it was very difficult to close the action. It also left the start of rifling marks on the bullet. So I set a little deeper and tried again. It took about 4 tries but I got the length to where the lever closed properly. Ended up with an OAL of 2.45. The crimp is just a hair above the top groove.

You can shorten your brass a hair so the crimp hits where you need.