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| Measure the neck of a loaded round. After firing, the fired case should be .002" larger or more in dia. The loaded round should not be larger in dia. then .290" You may have a tight neck chamber. |
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| As above, check for neck clearance (you might even invest in a chamber cast of your rifle), neck turning might be required.
As a rule, tight (minimum spec) chambers require less powder to acheive the same results (not as much powder energy is used to expand the case), just like neck vs FL sizing. Don't confuse tight necks with tight chambers, we're talking 2 diferent areas there.
Also how short is the throat, and are your bullets getting jammed into the lands? This is another area where a chamber cast can help you see whats in there. |
| | | Posts: 2124 | Location: Whittemore, MI, USA | Registered: 07 March 2002 | 
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| quote:
Originally posted by Burke:
...1)One problem that occurs almost always are signs of pressure regardless witch end of the spectrum ....2)Brass life is non existent,as i get a very slight bulge near the bottom of the case.....3)The 'smith who built my rifle cut my chamber to match(tight) dimensions.Should my loads lean towards the hot side to make these problems go away,or is there another problem that I'm missing...
Hey Burke, 1)If you would list the actual Pressure Signs you are seeing, it might help these folks out a bit.
2) It sounds to me as if you are describing the "Pressure Ring" located just above the point where the "Web" thins. If that is what you are seeing, it is something you should be able to see on every Centerfire case you load for and it is normal for this to occur.
(If you have Speer Manual #11, #12, or #13, let me know and I can tell you where to look in them ro see the Pressure Ring.)
In fact, you could(should) use the Pressure Ring Expansion(PRE) along with a set of 0.0001" capable Micrometers to get a reasonable idea of when you are approaching a SAFE MAX Load. Just measure the PRE on a box of Factory Ammo first, average the PRE, write that number on the box, full length resize those same cases, reload them with your Test Loads, and compare the PRE you get to what the Factory Ammo showed. When you get the same PRE - STOP!
Use a box of the High Intensity stuff from Hornady or Federal, or regular old Norma. All are loaded to a SAFE MAX Pressure.
3) I do not have any 25cal ammo that I can get my hands on at the moment, but from your description of the Neck Dimension "before and after firing", I would not think of your Chamber as being "cut... to match(tight) dimensions".
Don't take that as Bad News, cause it eliminates you having to go through Neck Turning in order for the Case Necks to be able to expand enough to release the Bullet without excess Pressure. |
| | | Posts: 9920 | Location: Carolinas, USA | Registered: 22 April 2001 |
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| quote:
Originally posted by Burke:
also my rounds are loaded off the lands by a little more than a hair.i use a stoney point oal gauge.so the gist i'm getting is maybe to back the loads off a hair(.5 grain) below the minimum load and start from there?
:Your load maybe to HOT. What are you loading- primer , brass , powder, weight of powder charge, bullets? |
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| I have experience with only one 25-06 -- a Tikka. Although I tried many combinations, I never did succeed in getting a load that gave good and consistent accuracy.
From my experience and what others have written, I suspect that this may be a cartridge that is persnickety to load for. (But my experience is limited to only one rifle in this cartridge, so what do I know?) |
| | | Posts: 5883 | Location: People's Republic of Maryland | Registered: 11 March 2001 |
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| quote:
Originally posted by Burke:
current load is/was rem brass,Win LR primer,52.9 gr of IMR 4831, 100 gr Nosler partition.
With IMR4831 my starting load would be 47.0 gr. with a max. of 52.0 gr. A chronograph would help to see what you fps is. The min. spec. target chamber may be the cause of you pressure. Just load with lighter charges of powder. |
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| quote:
Originally posted by Burke:
just for grins i checked some winchester factory rounds I 'd fired the other day.Unfired measured .283, fired measured .291-.292
The neck is ok. Does the factory ammo show any signs of high pressure?
[ 10-13-2003, 16:55: Message edited by: 243winxb ] |
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