Quickload will give you pressure values you require and it’s up to you to decide to take heed.
Flattened primers occur in factory bought ammo so not always a good indicator to back off,
Check other signs too like hard extraction and ejector / bolt marks on base of case .
It’s great to have as a guide and can be quite accurate if you put all the values in .
Like Amir says 43 gns of abc powder 10 years ago might be 40 gns from today’s abc powder that’s why you should always check current data etc
email...... stephenbarrow@ntlworld.com
Apologies for the tardiness of my reply, I couldn't face typing it out on a phone.
You N133 load is a little over the minimum charge given by viht load data and you are in the right ball park velocityt wise given viht data is from a 25" barrel, guessing yours is a little shorter?
Given that the velocity is around 300-400 fps below the maximum obtainable I would suggest that your flattened primers are not a sign of high pressure. Flat primers can be caused by headspace using full length resized brass or simply the shape of the primer pocket. Cratering around the firing pin ( unless you have a Remington with a sloppy firing pin hole like mine) is a better sign as is ejector and extractor marks, indicating the pressure is high enough to make the brass flow past it's elastic limit.
This limit depends on the make of brass but is generally somewhere between 50-70 kpsi.
If you are owrried about the primer pop one out and measure it to see if it has become "top-hatted" or flowed into the ring around the primer pocket.
The reason I mention this is that when you are using a published minimum load and achieving the published velocity for that load, it is likely that you are also achieving the pressure the lab got when deriving the data.
The magnitude of this pressure isn't actually very important to you, believe it or not. I say this as your aim is to have long brass life, as far as pressure affects your load, together with accuracy, etc.
So if you are using soft, let's say Remington, brass your maximum working pressure is lower than when using Lapua brass. Even if the internal case capacity of these two brands were identical I would bet you anything the Lapua will digest loads without any pressure signs that would have you hammering the bolt of your rifle open with a bit of wood had you used Remington.
The point to take away then is that the absolute value, saying this load is Xkpsi, is not a very useful number for relaoders; does your brass last for enough firings at your chosen load or not; if no then you are running your components too hard, if yes then no worries unless you have oil in the barrel, carbon in the throat, etc.
QL therefore becomes a tool that you can calibrate to your components and rifle with a lot of shooting and experimentation and so therefore cannot not save you any experimentation by definition.
The issue with compression is that simply stated, there is no issue.
Compressing rifle powders is very unlikely to give problems, certainly not from a pressure point of view if the powder being compressed is being compressed because it is slow burning for the calibre/bullet combo.
They in fact tend to shoot better than loads with lots of room in the case due to more consistent ignition.
That N140 load seems very low pressure, did it leave the case sooty?
I suspect it will chrono out at 2800-2900, meaning even less pressure than the N133 load.
I have noticed that you haven't given case capacities as per:http://www.6mmbr.com/Quickload.html
Quick load can't give you an indication of compression without an accurate, measured, case capacity; even then I think it's not really very relevant.
Try a long (12" +) drop tube.
"An infinite number of monkeys banging away at type writers for an infinite period of time will eventually reproduce Hamlet" Thanks to discussion forums we now know this to be untrue.
Have you measured the water capacity of some fired fired cases?
Fill% will depend on that figure as QL tends to use standard values which won't be the same as yours unless by chance.
If you are getting slightly higher velocities than predicted then your average case capacity might be smaller than that on the QL data file.
On the other hand, it might jsut be the barrel.
In the absence of a pressure lab my own tests for determining "max pressure" is to take a minimum capacity case to the range and load and shoot that one case until the primer pocket goes loose.
I look for ten firings plus for my hunting ammo, I like to err on the side of caution with hunting ammo, but some FTR shooters accept 2-3 for their 1000 yard loads.
"An infinite number of monkeys banging away at type writers for an infinite period of time will eventually reproduce Hamlet" Thanks to discussion forums we now know this to be untrue.
Thank you very much indeed for your observations and advice - very kind of you.
Yes, my barrel is 20" (rather than the 25" used for the Viht data) and the velocity seems OK. Interestingly, and on your suggestion, I have just looked at one of the flattened primers and it has "top-hatted" slightly (but no cratering around the firing pin depression). I use a variety of brass, and have never had any difficulty in extraction, but all primers with the N133 have exhibited flattening - which is why I was pleasantly surprised to see that the N140 showed no signs. Perhaps it is a slower round; I'll chrono some at the weekend and see what I get, but there was no sooting of the cases.
I'm now less concerned about the full case/slight compression; thanks for the link to the 6mmbr QL review. Very interesting.
Once again, thanks very much for taking the time to provide such a helpful response to my query.
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I wouldn't ask anybody to do that. I asked my original question not in anticipation of somebody crunching my data (there wasn't enough data to crunch in any case) but simply because I was experiencing what I thought were perhaps signs of excessive pressure from a very standard/modest load and was wondering whether QL would be of benefit in determining pressures under those circumstances. I think my question was answered quite satisfactorily and have thanked those who offered advice. I hope my question didn't come across as being a request to "crunch data". It certainly wasn't the intention.
i dont mind running data through quickload for others.....its only like me asking fellow members on a nihonto forum translating japanese kanji on sword tangs as i cannot read japanese lol
they dont complain so neither do i
email...... stephenbarrow@ntlworld.com
And very grateful we are for members like you!
I would happy to give reasonable advice and assistance to others
here too. After all, the shooting community is quite small; we need to stick together.
If I had a windows laptop I would purchase quickload. I hear that the developer has no interest in developing a version for Mac OS.