Primer Remanufacturing – Red Phosphorus Mixtures
This testing sequence will be focused on an old Primer Mixture from the 1940’s using Red Phosphorus. The mixture was derived from a 1944 Paper on Primers entitled Primers for Small Arms Cartridges by M. J. ALBERT and H. F. OELBERG. The paper was transcribed into a digital .pdf format by Marshall Thompson and copyrighted in 2017. A copy of the multi-page paper can be found at:
https://www.aardvarkreloading.com/re...%20Oelberg.pdf
Red Phosphorus was explored by the US Government as a primer mixture, and actually used in 1949 as the “P-4 Formula. https://www.bevfitchett.us/chemical-...positions.html
About 1949 Frankford Arsenal manufactured an unusual priming mixture known as the P-4 primer (coded FA675):
Stabilized red phosphorus 18% Barium nitrate 82%
Although this was a simple, relatively safe mixture, and was a satisfactory primer, it was discontinued after a very short period because of two major disadvantages. It was shown that copper, bismuth, silver, iron, and nickel increased the oxidation rate of red phosphorus to acidic compounds. Primer cups had to be zinc plated to prevent contact with copper. The red phosphorus had to be of high purity, and it was necessary to remove the major impurities (iron and copper) from commercial red phosphorus before use, and to coat the purified material with up to 7.5% aluminum hydroxide which inhibited oxidation.
Although the P-4 primer was only in use for approximately 1 year, it was further improved in 1961 by coating the stabilized red phosphorus with PETN, RDX (cyclotrimethylenetrinitramine), or TNT giving the following primer mix:
Stabilized red phosphorus 25%
However, red phosphorus primers never achieved widespread use, presumably due to manufacturing difficulties.
Of interest is that the use of Red Phosphorus was recently resurrected as a potential “GREEN PRIMER”. The company ATK put out a Paper/Slide show on using Red Phosphorus as a key component in US Primers entitled: Non-toxic Heavy Metal Free Primers for Small Arms Cartridges – Red Phosphorous Based. Introducing ATK Lake City’s P4rimerTM .
https://ndiastorage.blob.core.usgovc...usky_520pm.pdf
The use of Red Phosphorus in home Remanufacturing of Primers has the same handicap of many formulas in that some components are difficult to acquire. I was able to acquire 200 grams (about ½ pound) for making primers after a 3 month search/wait.
Primer Remanufacturing – Red Phosphorus Mixture #1.
The first test will be with the mixture derived from Chapter One of the Paper Primers for Small Arms Cartridges.
The formula used is a “Volume” ratio. The paper called out using an empty 22 LR case as the Measuring device.
Lead Nitrate 20%
Aluminum 20%
Red Phosphorus 20%
Barium Nitrate 40%
I wanted to measure by weight instead of volume – so I weighed a 22LR case filled full for of each of the chemicals and established the following Weights in Grains for the Mixture. This represents One Batch of Mixture.
Lead Nitrate 14.1 grains
Aluminum 0.9 grains
Red Phosphorus 2.7 grains
Barium Nitrate 14.8 grains
Total 32.5 grains
The filling & compacting from the reference called for filling the primer cup, packing with a wooden match, refilling and placing a paper foil on top followed by a primer anvil. I wanted to follow the processes I previously used in my other postings on Primer Remanufacturing since I had established personal success and reliability. I selected 10 Brass Primer Cups and sized them in the NOE Large Primer sizing die (cups have been reused 5 to 10 times each). I filled each cup using the mixture above; leveled at the top of the cup. I placed a Paper Disk foil cut from Cash register tape using a ¼ inch hole punch on top of the filled cups; and then compressed the disk/primer mixture on each primer using the same technique described in post #27 of my thread:
https://castboolits.gunloads.com/sho...readings/page2
The original description called for a “Dry Mix”; but I have found these to be problematic as some primer mixture seems to find a way to leak out of the cups when handled. I wanted to see if a “Wet Mix” could be used with this mixture so I loaded 5 rounds with a “Dry Mix”; and I used a 20:1 mixture of Alcohol and Varnish to wet the Foil & Primer Mixture underneath for 5 primers – let dry for 24 hours. All 10 primers were loaded as follows; but the Wet Primers are identified with a Red Marker to allow assessing performance of each process.
Load Data to be used in the Test will be:
Red Phosphorus mixture #1. Individual Large primer cups use ~ 0.55 grains for each primer cup.
Rifle: Remington 700 ADL Varmint .308
Barrel Twist: 1 in 12
Boolit: NOE 311041
Ballistic Coefficient: .220
Brinnel Hardness: 20
Bullet sized: .310
Alloy: 96% Lead, 3% Antimony, 1% Tin
Bullet Lube: Powder Coated with Eastwood Blue Paint.
Gas Check: Ameri-max Aluminum 0.14”
Powder: BLC-2 – 32 Grains with Dacron Over Powder
Primer: Remanufactured – Red Phosphorus Primer Mixture #1
Case: Mixed military and commercial Brass
OAL: 2.585 inches
Distance: 100 Yards.
Pictures of groups will be published after I test fire these primers.
2 Attachment(s)
Primer Remanufacturing – Red Phosphorus Mixture #1 Test Targets
Got to the Range this morning to fire the 10 Test rounds developed. Five were dry primer mix "Packed Only" similar to original instructions. The other five were "Wet Mix" with a 20:1 ratio of alcohol (91% alcohol and 9 % water from Walmart) and Varnish from Home Depot. Unfortunately I forgot to bring the tripod with me so I was unable to get a Chronograph reading as I originally intended.
Dry Mix for Red Phosphorus (Mixture from Chapter II) test target:
Attachment 317181
Group Size at 100yards was 4 & 3/8 inches (4 & 3/8 tall by 2 & 1/4 inc wide)
Attachment 317182
And; the Wet Mix Red Phosphorus (Mixture from Chapter II) Test Target:
Group Size at 100 Yards was 2 & 5/8 inches (only 1/2 inch tall, but 2 & 5/8 inches wide).
My original concern (not being a chemist) was that I might contaminate the primer mixture or have a reaction using the 20:1 wetting mixture. This is apparently not an issue with this chemical make up. In fact; the wet mix on a limited sample ( 5 shots and 5 shots); is exhibiting a significantly smaller group on paper. I am currently attributing that to the Primer Mixture being hardened into a single pellet with the mixture - keeping the mixture all in the cup and providing a harder surface for the Reaction when the firing pin and Anvil crush the pellet.
I will be looking at some other Adaptations of Red Phosphorus in the Primer Mixture in the next few weeks/months. Later this weekend I will attempt to break down the fired primers and see if there is anything to see in the residue. The brass was cleaner after firing or this Primer Mixture compared to many of the H048 and FH-42 Tests I have conducted; but there was powder fouling on the mouth, and some slight fouling on the sides of the cae.