.243 bullet seating question

[French hunter]

Hi all, I have a question for anyone that can give me a pointer with not necessarily a problem but a slight worry I have with my. 243 tikka m595 master sporter.
Question I have is when reloading I use 100grn sierra spitzer boat tails.
Just recently I have purchased a hornady modified case to check for seating distance, before I had modified one of my own fire formed cases and the length from ogive measuring was 2.285 tho so been backing them off 20 tho but was noticing tight chambering. Thought nothing of it, but now using the new hornady modified case I am getting 2.115 tho backed them off 15 tho so now seating at 2.100 tho. My worry is that they look really really short in the case. Checked against a schematic for a factory load look short too me.

 

[DVS1]

Try a YouTube search for Eric Cortina and his seating depth video...very interesting

 

[French hunter]

Thanks will do.

 

[DVS1]

Seating Video

there you go mate

 

[French hunter]

Just watched it, thanks might help, as i do what he talks about but normally Increments of 5 tho. Going to the range tomorrow and see how the new bullet depth works out. Cheers for that.

 

[xavierdoc]

Is the brass too long or insufficiently resized (neck sized only?)

Carbon ring in throat, giving false reading of the leade?

 

[Iamtheferryman]

I load my tikka m590 20 thou off the lands.

I did have an issue with tight chambering but after looking at my brass a trim and a full length resize sorted the issue.

All the best

 

[User00044]

1st , there's something wrong with your measuring technique . There's no way you should get 0.165" difference . The bolt face to lands aren't a variable , the brass however is but to see that amount of case growth is worrying.
If you've measured correctly , 0.015" jump wouldn't be causing chambering issues. I suspect @xavierdoc is on the money your brass has not been sized correctly . If sized insufficiently the cases will become longer as the die may size the body , squeezing and lengthening the case if the shoulder doesn't engage the die . A dry expander will exacerbate the problem by drawing at the neck.
Before you go any further, may I suggest that you check your sized brass chambers .
My other suggestion would be to load to factory spec' , in the case of Sierra 100 grain SBT , that would be 2.650 . The SBT is a tangent ogive, so once seated may give the impression of being short compared to something with a secant or polymer tipped bullet .
If you're just starting out , you're throwing yourself in at the deepend starting with seating depths , master the basics . Why give yourself a headache ?

Enjoy

 

[French hunter]

Thanks all, went to the range this morning and don't think I will be worrying any more as managed to shoot a 30 at 100m. Out here they use a target with numbers on out to 1 and into 10 each number ring is an inch wide so to get a 30 well Happy. Been reloading now for about 25 years and still have a lot to learn. Would show the picture but can't work out how to upload photos on this bit.

 

[French hunter]

1st , there's something wrong with your measuring technique . There's no way you should get 0.165" difference . The bolt face to lands aren't a variable , the brass however is but to see that amount of case growth is worrying.
If you've measured correctly , 0.015" jump wouldn't be causing chambering issues. I suspect @xavierdoc is on the money your brass has not been sized correctly . If sized insufficiently the cases will become longer as the die may size the body , squeezing and lengthening the case if the shoulder doesn't engage the die . A dry expander will exacerbate the problem by drawing at the neck.
Before you go any further, may I suggest that you check your sized brass chambers .
My other suggestion would be to load to factory spec' , in the case of Sierra 100 grain SBT , that would be 2.650 . The SBT is a tangent ogive, so once seated may give the impression of being short compared to something with a secant or polymer tipped bullet .
If you're just starting out , you're throwing yourself in at the deepend starting with seating depths , master the basics . Why give yourself a headache ?

Enjoy

Hi, thanks for that, I use a lyman case trimmer so cases aren't too long as check every time I reload. Just I think the problem was with my own modified case and then switching to the hornady case gave such different readings. Have been loading for 25 years and this is the first time I have come up against this but you live and learn everyday. Went to the range this morning and got 3 bullseye without touching anything so won't be worrying now. Would show photo but can't work out how....getting old and technology is not my friend...lol

 

[User00044]

Hi, thanks for that, I use a lyman case trimmer so cases aren't too long as check every time I reload. Just I think the problem was with my own modified case and then switching to the hornady case gave such different readings. Have been loading for 25 years and this is the first time I have come up against this but you live and learn everyday. Went to the range this morning and got 3 bullseye without touching anything so won't be worrying now. Would show photo but can't work out how....getting old and technology is not my friend...lol

My apologies, I thought you were implying you were new to handloading.
I wasn't implying the trim length be the problem , more the possibility of a total lack of headspace created by an incorrectly set sizing die which was causing the stiff chambering .