Pressure Load ??

C

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What is meant in reloading terms of 100% or 85 % of pressure.
Some one has commented of being over 100% pressure with a compressed load, can any one clarify??
I'm just following my reloading manual and find some casings almost over full, others not yet the manual says it's ok and my groups are good, never had any problems but don't want too also.
Any help is great.
Thanks
Curly
 
What they are referring to is the maximum SAAMI or CIP pressure for the cartridge.

http://en.wikipedia.org/wiki/Sporting_Arms_and_Ammunition_Manufacturers'_Institute

Each cartridge has a maximum pressure rating. This is a standard. The reason you have a standard is so that gun manufacturers can design guns that can withstand that maximum pressure and ammo manufacturers don't make ammo that exceeds it.

Generally, loads listed in your loading manual should be safe for commercial firearms of the caliber in question. However, every gun is different and you should familiarize with pressure signs and work up your loads slowly in order to ensure you don't have any problems.
 
You may have seen someone mispeaking who meant to say 110% capacity. It is useful to know what case capacity a given load is.

While it is possable to load compressed loads it can be a PITA and I would like to know this beforehand if I want to avoid a compressed load - or going the other way, I might not want a load less than 90-% of capacity.
 
Whether a load is compressed or not does not determine the "Pressure" of the load--in some small cases a heavily compressed load of slow powder will not come anywhere close to the maximum pressure for the cartridge while a very small charge of fast powder may exceed it.

FWIW, 44Bore
 
The term 110% capacity another term I have heard, if a load of powder eg:
comes near the top of the case neck, then you seat the bullet .... making it compress is this something to worry about, this is what I get with my most accurate load of 4831 IMR 165gr. Nosler partition, I have never had any problem with this. I try to avoid the IVI or Imperial Brass to avoid such a full casing, as said before the federal or winchester brass is better. not as compressed.
tanx gents
Curly top
 
The term 110% capacity another term I have heard, if a load of powder eg:
comes near the top of the case neck, then you seat the bullet .... making it compress is this something to worry about, this is what I get with my most accurate load of 4831 IMR 165gr. Nosler partition, I have never had any problem with this. I try to avoid the IVI or Imperial Brass to avoid such a full casing, as said before the federal or winchester brass is better. not as compressed.
tanx gents
Curly top
 
No, just the fact that its compressed that much doesn't mean that it isn't perfectly safe. I have some very safe and accurate loads that are probably compressed around that much. Winchester brass has one of the highest capacities, so a given charge won't be as compressed in it as it will be in an IVI case.

You didn't specify a caliber or a charge weight, so it isn't possible for anyone to judge whether or not your specific load is safe. However, one red flag that immediately pops up in your post is that you appear to be saying that you're interchanging the make of brass in your load without adjusting the charge for the difference in case capacity. Without knowing anything else about your load, that alone causes me great concern. I sincerely hope you've gotten the load in question from a reloading manual or other reputable source.
 
Thanks for your concern.
I use the nosler manual, and use 2 loads.
IMR 4831 - 47 gr. with a 165 gr. partition.
and IMR 4831 - 49 gr. and again 165 gr. Partition.
Very happy with both loads, I group the brass together, all IVI or Win or Fed.
Been shooting it for 30 years now , no problems, I just don't know what 110% capacity and pressure loads meant.
Thanks
Curly
 
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