Minimum COAL

[Stein]

Quick question for experienced reloaders, I am doing a seating depth test starting at the maximum magazine length and going shorter from there in .003 increments.  The max mag length is well under touch or jam length.  55.0 H4350 behind 168 TSX, so closer to min load than max (55.0-59.0 from Hodgdon, but for wrong bullet as Barnes doesn't have H4350 data)

I know that as I go shorter, the pressure will go up and the velocity will go up (assuming everything else stays the same).  After the first round of testing, I'm showing a definite improvement in group sizes as I go smaller, so I want to go down several more steps to see if I can tighten them up more and where a nice band is.

My question is whether there is a safety issue with going too short?  I'm checking to make sure the load isn't compressed and would stop if I couldn't hear powder freely shaking in the loaded round.  My concern is that even though it's a mild load, I don't have any way to understand if the increase in pressure will go above SAAMI or not or if it's a minor or major change in pressure as I go shorter.

[BULLBLASTER]

It should be a pretty minor change in pressure with shortening coal. With a low pressure load range i would not be concerned at all. Just keep an eye out for any pressure indicators.

[Jonathan_S]

That's a real mild load (WSM?) I think you'd have a real hard time hitting pressure with a lightweight Barnes and that charge.

[Stein]

That's a real mild load (WSM?) I think you'd have a real hard time hitting pressure with a lightweight Barnes and that charge.

30-06, forgot to mention.  Yeah, it's pretty light but was the most accurate in my load testing.  I went all the way up until the primer started to bulge and this was the clear winner.  I had a decent velocity node around 57, but not as good and nothing exciting above that.

[Jonathan_S]

Sorry I "jumped" to conclusions thinking it was a short action COAL problem.

[Stein]

No problem, I assume most people shoot 30-06 I guess.   

[CaNINE]

Stein - 0.003 is a pretty small increment to work with, let alone maintain on a reliable/repeatable basis.  I suggest working with a minimal increment of 0.010 when testing seating depth sensitivity. 

[Mtnwalker]

Stein - 0.003 is a pretty small increment to work with, let alone maintain on a reliable/repeatable basis.  I suggest working with a minimal increment of 0.010 when testing seating depth sensitivity. 

Barnes recommends starting at .050 and working in .025 increments I believe

[buckfvr]

You should be recording velocity data at this time as a spike in velocity will correspond with a spike in pressure.  Velocity node and accuracy go hand in hand.

[NWShooter]

Stein - 0.003 is a pretty small increment to work with, let alone maintain on a reliable/repeatable basis.  I suggest working with a minimal increment of 0.010 when testing seating depth sensitivity. 

I agree. I would do it in .020 increments. Then fine tune from there.

[jasnt]

I agree.  .003 is way too small     I use .03 and then fine tune in .005” increments.  You have to test about 75 different seating depths to even come close to a pressure issue with that load if not more!start at mag length, load 3-5, go .030” deeper load 3-5 more.  Continue that till your jumping more than .150.   Choose the best group.   Test 1gr on each side of your powder load in 1% increments.   Choose the best es and then fine tune your seating depth in .005” increments    Then if you still think you can do better switch to Berger bullets 🤪

[Magnum_Willys]

I go .010 to .035 in .005 steps.   If nothing good use .060, .090, .0120 to see if close then refine .005 steps. 

[mountainman]

I go .010 to .035 in .005 steps.   If nothing good use .060, .090, .0120 to see if close then refine .005 steps. 

This👆

[TheArmoredShop]

You can really push a casing a long ways before you see stress. I was blowing holes in my primers of my 300 winmag at 85 grains of H1000 highly compressed load before I backed off 1% to 83.7 still compressed but everything held fine. Just go slow. Once you start flattening primers or blowing out the primer, you’re good. Primers are usually the first thing you see other than an extractor mark

[Jonathan_S]

How many firings you get at 5 grains over book max?