in2anity wrote:bladeracer wrote:Yes, they were converted by professionals weren't they, people that would've done the calculations and determined that they would work just fine?
My understanding is they were converted with consideration to the commonwealth 762 NATO ammo available in that era, i.e. 144gr. Not just any 308w available.
bladeracer wrote:Vince24 wrote:In any case, my rifle is a wartime Long Branch, so I will not exceed 43.5, starting from 41.5.
Cheers
My No.4 Mk1* is a 1943 Longbranch.
My standard load with the 150gn bullets is 36gn of AR2206H.
I'm using S&B brass for this rifle. Filled to the top it holds 48.9gn of AR2206H.
bladeracer wrote:in2anity wrote:bladeracer wrote:Yes, they were converted by professionals weren't they, people that would've done the calculations and determined that they would work just fine?
My understanding is they were converted with consideration to the commonwealth 762 NATO ammo available in that era, i.e. 144gr. Not just any 308w available.
I did find a page that says the original L2A2 Ball 144gn made 50,000psi, at 2700fps, but I haven't found a supporting source yet.
https://sites.google.com/site/britmilammo/7-62mm/7-62mm-nato-ball
As current 147gn M80 ball makes 2800fps at 60,000psi I'm wondering if perhaps the Brits simply took their pressure measurements using a different method?
According to this guy https://www.youtube.com/watch?v=sE3WWgyJ3Pw the current F4 Ball is a 43.2gn charge behind a 145.5gn bullet making 2800fps in a 22" barrel, so virtually identical to US M80 Ball, and only 4% hotter than the 1954 stuff.
Vince24 wrote:ADI 16, that’s my head stamp! But 43.2 grains of which powder??)
Vince24 wrote:bladeracer wrote:Vince24 wrote:In any case, my rifle is a wartime Long Branch, so I will not exceed 43.5, starting from 41.5.
Cheers
My No.4 Mk1* is a 1943 Longbranch.
My standard load with the 150gn bullets is 36gn of AR2206H.
I'm using S&B brass for this rifle. Filled to the top it holds 48.9gn of AR2206H.
Just to avoid any misunderstanding, is yours in 308w as well? That seems a very mild load (but it seems you like those mild loads in 2206H in military rifles )
Vince24 wrote:ADI 16, that’s my head stamp! But 43.2 grains of which powder??)
bladeracer wrote:But these guys are telling you that this load is 10,000psi higher than your rifle was designed to cope with.
Over The Hill wrote:I am loading Speer 150g Soft Point Boat Tail Spitzers with 44g AR2208 which ADI lists at 43600 psi.
in2anity wrote:bladeracer wrote:But these guys are telling you that this load is 10,000psi higher than your rifle was designed to cope with.
I'm not - i think that ammo is around 50kpsi, perhaps a touch more, as i've been saying all along.
in2anity wrote:Over The Hill wrote:I am loading Speer 150g Soft Point Boat Tail Spitzers with 44g AR2208 which ADI lists at 43600 psi.
That seems like a mistake in the ADI table to me - look at the Nosler loads above, of the same weight. I reckon it's a misprint and should be CUP.
Over The Hill wrote:I am following this conversation with great interest as I also have a No.4 in 308W which was built for me specifically as a range rifle and in 308 as I already shoot and load this calibre so I didnt need to outlay anything for ammo or loading gear, also I like being a little bit left of mainstream. ADI has load data for the 308 with 150g pills. I am currently using 150g Hornady Soft Point Interlocks with 12g Trailboss for 50M which will be approx 26000 psi and for 100-200M I am loading Speer 150g Soft Point Boat Tail Spitzers with 44g AR2208 which ADI lists at 43600 psi. I dont see any need to load higher as I wouldnt see any noticable improvement using irons and have no desire to increase pressures. I seem to remember reading on another forum that back in the day the Canadian DCRA imposed a weight limit of 155g and even the gunsmith who built my No.4 also said not to use projectiles over 155g whether factory or handloads. I have too many $ invested in this rifle and want it to last my shooting life so I am happy to treat her nice and stick to listed loads where the pressures are published. Note, ADI table is for 24" barrel, std No.4 is 25" so close enough for a good estimate.
in2anity wrote:Over The Hill wrote:I am loading Speer 150g Soft Point Boat Tail Spitzers with 44g AR2208 which ADI lists at 43600 psi.
That seems like a mistake in the ADI table to me - look at the Nosler loads above, of the same weight.
I reckon it's a misprint and should be CUP.
Over The Hill wrote:in2anity wrote:Over The Hill wrote:I am loading Speer 150g Soft Point Boat Tail Spitzers with 44g AR2208 which ADI lists at 43600 psi.
That seems like a mistake in the ADI table to me - look at the Nosler loads above, of the same weight.
I reckon it's a misprint and should be CUP.
I am not so sure its a misprint
If I look at the ADI table for 150g speer SPBT with max 47.5g AR2208 nis shows pressure of 58400 PSI. If this was in fact a misprint and meant to be 58400 CUP then the pressure in PSI would be well north of SAAMI spec and I doubt that ADI would be publishing recommended loads that exceed SAAMI
In any case for the 44g load I am using whether 43600 psi or 43600 CUP (approx 48200 psi) it is in my opinion still a safe load for the No.4.
Vince24 wrote:As to which powder, well not easy to say, see pictures.
From top to bottom you have the ADI powder, some 2206H and then some 2208.
Vince24 wrote:The ADI father looked like 2206H to me but anyway, it has become purely academical by now.
bladeracer wrote:Over The Hill wrote:in2anity wrote:Over The Hill wrote:I am loading Speer 150g Soft Point Boat Tail Spitzers with 44g AR2208 which ADI lists at 43600 psi.
That seems like a mistake in the ADI table to me - look at the Nosler loads above, of the same weight.
I reckon it's a misprint and should be CUP.
I am not so sure its a misprint
If I look at the ADI table for 150g speer SPBT with max 47.5g AR2208 nis shows pressure of 58400 PSI. If this was in fact a misprint and meant to be 58400 CUP then the pressure in PSI would be well north of SAAMI spec and I doubt that ADI would be publishing recommended loads that exceed SAAMI
In any case for the 44g load I am using whether 43600 psi or 43600 CUP (approx 48200 psi) it is in my opinion still a safe load for the No.4.
The start charge is 43,600CUP, not psi, the max charge is 58,400psi. The error is in the use of two different measuring systems but listing both as psi.
SAAMI spec is 60,000psi for .308Win.
Over The Hill wrote:Out of interest I contacted ADI questioning their data in case of misprint. To my pleasant surprise ADI have replied with a letter that states: We can confirm that the data which you are referring to is accurate based on our records.
Full letter text below FYI as it contains some interesting info regards the accuracy of these published tables
Thank you for your enquiry of 28/9/2022 with regard to reloading using ADI Sporting powders.
Please find attached our latest test load data for .308 Winchester.
We can confirm that the data which you are referring to is accurate based on our records.
Owing to the effect of variations within allowable manufacturing tolerances for cartridge components made by different manufacturers, firearm variations and conditions, operating temperatures etc, pressures developed by any given rifle or pistol load can vary significantly from those that apply to our recommended loads. The two loads you are referring to have been generated at different times with different manufacturers component lots and in different barrels so there is likely to be some variation.
We note that there is no ‘rule of thumb’ to convert CUP to PSI so the two loads that you are referring to cannot be directly compared.
Older data and some of the load data supplied by Hodgdon Powder Company has been measured in copper units of pressure (cup), which is mechanically using a copper slug called a “crusher”. The crusher is placed in a fixture over the chamber where a hole passes through the barrel to the chamber. When the cartridge is fired, the resulting gases cause the “crusher” to flatten. The “crusher” is measured and the result is then converted to pressure by comparing to a tarage table. Our more recent data is measure in pounds per square inch (psi) by calibrated Piezoelectric transducers.
Our published test load data is only ever intended to be used a guide and you should always work your loads up using your components and firearm until you find your optimum safe load.
Ensure that you begin your load development at the suggested starting load. Carefully monitor your rifle and cases for signs of excessive pressure like badly flattened primers or difficult bolt lift.
Extreme caution should be taken and loads should be worked up accordingly. Refer to our website at http://www.adi-powders.com.au or our 10th edition handloaders’ guide for more information, warnings and reloading safety.
We thank you for using ADI Sporting Powders.
Yours sincerely,
ADI Technical Centre
straightshooter wrote:Pretty well all of these loading calculators are a flashy interface applied to the Homer Powley ballistic calculations developed in the early 60's.
The illusion of predictable precision in these modern calculators is just that, an illusion.
Trust only data from reputable laboratory tested loads such as ADI/Hodgdon and to have a chance of getting the predicted results one must follow the recipe exactly but the result will still depend on the remaining variable, ones rifle.
Vince24 wrote:It does not replace the reloading data from the manuals or from ADI, it does not replace your brain, but it's a useful complement to understand what you're doing. Just that. I don't use it for accuracy, only the group on your target can tell you that!