Seated bullets a little too deep - Dangerous? High pressure?

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Seated bullets a little too deep - Dangerous? High pressure?

Post by Gogetem » 06 Jan 2015, 7:59 am

Hi Guys,

I have hand loaded my first batch of SST in 150gn using ADI 2206H. Data suggests COL of 2.800.

I have loaded few rounds at start load of 43gn at COL at 2.807. However, after adjusting my lee Classic loader in order to get COL close to 2.80 I ended up loading few rounds on a higher load of 43.5gn at COL 2.779 before I finally managed to get my COL at 2.804

Never exceed load for jacketed bullet 150gn on ADI and Lee's Handloading guide for this powder is 45.5gn, though I have stopped loading at 43.5gn, apart from effecting accuracy will these rounds be dangerous to use given the under sizing leading to high pressure?

Size of the bullet is 1.193" , I used CCI primers and the brass were once fired on tikka t3 with cartridges neck sized only

Please advice of your thoughts.

Regards
Last edited by Aster on 06 Jan 2015, 12:54 pm, edited 1 time in total.
Reason: Moved to a dedicated topic for you since this is a bit more of a particular question than the original topic.
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Re: Seated bullets a little too deep - Dangerous? High press

Post by squirrelhunter » 06 Jan 2015, 12:53 pm

I've loaded some 110gr .308 for my Scout trying a low recoil load. The bullets were so short I couldn't seat them anywhere near 2.8"

As it turns out they were too inaccurate and I haven't done them since, but from memory COAL was 2.710"
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Korkt » 06 Jan 2015, 1:27 pm

(Assuming we're talking about your .308 here)

The 2.800" COAL is an accepted standard but it's not an absolute that must be adhered to down to the last thou.

I'm sure you've read people setting their seating depth to get the bullet as close to the lands of the rifling as possible which is often above the 2.800". Might be 2.810 or 2.815 or 2.820... Depends on the rifle, but isn't a problem when matched correctly.

Same goes for the reverse. Typically the reasons for shorter COAL will be lighter bullets which don't have very long bodies. If they're seated high there isn't enough bullet in the neck for it to be seated securely and they'll be bumped lose and move or fall out.

0.02" below is nothing to be worried about at all.
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Re: Seated bullets a little too deep - Dangerous? High press

Post by RDobber » 06 Jan 2015, 1:33 pm

Gogetem wrote:apart from effecting accuracy will these rounds be dangerous to use given the under sizing leading to high pressure?


From what you've described, I'd say safe as houses.

For the .308 0.02" below the stated COAL is nothing to worry about.

ADI data already has a significant safety margin, being 2 gr below max you've only added to it. (Going too low is a safety issue, but that's another topic. You're above minimum in this case so not relevant here)

As the loads even compressed? If you shake one of the 2.779" cartridges can you hear the powder jostling around?
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Gogetem » 06 Jan 2015, 3:40 pm

Korkt wrote:(Assuming we're talking about your .308 here)


My Bad :( forgot to mention the critical bit. Yes, .308.

Most of the discussion I read revolved around COAL being a bit over sized hence sought clarification on undersized cartridge. Thanks heaps for the info :)
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Gogetem » 06 Jan 2015, 3:46 pm

RDobber wrote:As the loads even compressed? If you shake one of the 2.779" cartridges can you hear the powder jostling around?


Hi RDobber,

Thanks for the info. What concerned me was that I may have possible compressed the load as from memory 43.5gn filled the case upto the shoulder (case size 2.009").

I will give the cartridge a bit of shaking to see if the powder jostles little bit or not.
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Re: Seated bullets a little too deep - Dangerous? High press

Post by brett1868 » 06 Jan 2015, 6:51 pm

I'm assuming you used the exact projectile listed in the reloading data and your measuring base to tip on the cartridge. +/- a few thou on this measurement is nothing to get worried about as the actual projectile itself is probably +/- a few thou itself.

Measure a few projectiles and you'll notice that they can vary in length easily by a few thou. To work out seating depth I use a Hornady O.A.L gauge to measure the distance from the shell base to where the Ogive of my projectile meets the rifling. I then subtract 1 thou and that's the Max O.A.L I use.

I set up my seating die accordingly and use a Hornady Bullet Comparator tool in the callipers to check and adjust till spot on. When developing a load one of the variables I use is seating depth and since no 2 chambers are identical it's something you need to work out for your particular rifle.
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Jack V » 06 Jan 2015, 7:14 pm

It sounds ok to me but at 45.5gr you are at the stated max from the ADI guide. However "if" 43.5gr was fine then 45.5gr should not be excessive dangerous pressure but possibly a stiff load that will kick a bit extra.

It is always best to work up to the stated max just to make sure your gun and load combination can handle it. Some guns can be very tight in the chamber and bore and if the case capacity is also tight they show pressure signs earlier than other guns.
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Gogetem » 07 Jan 2015, 4:57 pm

brett1868 wrote:I'm assuming you used the exact projectile listed in the reloading data and your measuring base to tip on the cartridge. +/- a few thou on this measurement is nothing to get worried about as the actual projectile itself is probably +/- a few thou itself.


I used the load mentioned for 150gn jacketed body for a ballistic tip, that's the closest I could find on ADI- could not find data on Hornady's website for the SST.

I need to invest more in tools- slowly and steadily I will get there :)
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Gogetem » 07 Jan 2015, 5:00 pm

Jack V wrote:It sounds ok to me but at 45.5gr you are at the stated max from the ADI guide. However "if" 43.5gr was fine then 45.5gr should not be excessive dangerous pressure but possibly a stiff load that will kick a bit extra.

It is always best to work up to the stated max just to make sure your gun and load combination can handle it. Some guns can be very tight in the chamber and bore and if the case capacity is also tight they show pressure signs earlier than other guns.


I will see how I go with the 43 & 43.5 this weekend at the range and try out some loads at .5 increments to max load next time around to see which one shoots well on my rifle
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Lyam » 07 Jan 2015, 8:45 pm

Gogetem wrote:I used the load mentioned for 150gn jacketed body for a ballistic tip, that's the closest I could find on ADI- could not find data on Hornady's website for the SST.


That's fine.

There isn't load data for every bullet. Broad groups like match, ballistic tip, flat base etc. is all you'll get.

Bullet weight and the correct powder charge is more important.
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Re: Seated bullets a little too deep - Dangerous? High press

Post by Jack V » 08 Jan 2015, 11:00 am

Gogetem wrote:
Jack V wrote:It sounds ok to me but at 45.5gr you are at the stated max from the ADI guide. However "if" 43.5gr was fine then 45.5gr should not be excessive dangerous pressure but possibly a stiff load that will kick a bit extra.

It is always best to work up to the stated max just to make sure your gun and load combination can handle it. Some guns can be very tight in the chamber and bore and if the case capacity is also tight they show pressure signs earlier than other guns.


I will see how I go with the 43 & 43.5 this weekend at the range and try out some loads at .5 increments to max load next time around to see which one shoots well on my rifle

That is a good plan .
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