Question about seating depth.

[jgh4445]

I have a BRNO Mod 22F in 7X57. I'm working up loads and am wondering about seating depth. The COL MAX is 3.065 according to the books. I used an OAL gauge and determined that my max could be as long as 3.19. Does anyone have any experience with this model rifle? Do you think it would likely prefer to be jammed into the lands or would it like to be seated 5 to say 20 thousandths off? Its gonna have to be at least .003 off the lands due to needing at least .284 inches of bullet in the neck of the case. The magazine length won't be an issue.

 

[Blue68f100]

All guns like something different. Depending on bullet some like a long jump, some short, some where in between. Your limiting factor may be magazine max length. I always start off where the bullet mfg suggest for the OAL. Once I find my load I then start playing with the OAL.

If it's used for hunting, I do not want it to jam into the rifling, just encase I have to eject the round. The last thing you need is for powder to go everywhere into your action.

I don't chase the lands either. Once I find my load I stick to it. The only changes I may make is when I change bullet lots. Then I use the ogive measurement to put me back to where I want.

 

[mdi]

FWIW; seating depth, chasing the lands is the last thing I do for finding accuracy. I often don't get that far for good loads. My best rifle handload for my 308 is military used brass (7.62x51) with IMR4895 and Hornady bullets seated to book OAL. Many 7/8" groups @ 100 when I'm doing my part...

 

[AJC1]

Some bullet shapes are known to be a lot less picky with seating depth. If your not in a shooting sport that wins and losses are measured in thousandths of an inch over a hundred rounds dont bother. The easy way to know is if if you have the reamer or the print and your Smith is well known. Buy good bullets and run the Berger seating depth test.

 

[koni]

I think your on the right track. When I do a load work up I start with jam, then work my way off the lands in .005 increments. I shoot 3-5 shot groups. (depends on how many primers I have left) till I get the group I want. Then I confirm the load and seating depth with 10-20 round test. Proof is always on the paper and that’s the best way to read how well your load is doing.

 

[jmr40]

I start by loading one round as long as possible that will still fit the magazine. If that round feeds out of the magazine without hitting the lands that is where I start. I'll load up a batch and head to the range. If I get the accuracy I want then I'm done. I might get better accuracy with them seated longer, but unless I want a single shot I can't. And I don't want a single shot.

Most of the time that gives me what I want. But if I need to experiment, I can always seat the rest of that batch a little deeper and see what happens. That is pretty rare.

I don't chase a specific OAL.

 

[AJC1]

Examples of jump in my .308
155 lapua secnar at book length of 2.800 oal is jumping. 325" this load shot 1moa at 100 yards with a random 42.5 charge and no workup provided to me by my dad before he passed. This shot in a factory rem r5. If you have a factory barrel most are deeeeeeep and you work in the seating ranges available.