Being a handloader for a while without a chronograph and only using primers to judge load pressure. I learned about primer thickness naturally. Military and magnum primers are both thicker but for different reasons. Since a mag is going to be at higher pressures u don’t want a blown out primer hole or it to badly crater so their thick. Military rifles have loose firing pins and are auto loaders so u don’t want slam fires from heavy firing pins. Magnum primers are more powerful to reliably burn compressed slow burning powders. I use to load till I got good craters and then back off a little before I had a chrono. U learn quick what primers are hard and soft.
Saw someone testing small rifle primers when he got hang fires and found that load density was the reason for it. So when I load my small primer 308,708,6.5 creed I look for powder the gives good case fill. Always interesting videos guys. Live free and be safe..
The problem with the water cooled machine gun was hauling all the parts. What replaced that system was barrels that were quick to swap like on the M60. You always carried an extra barrel.
🕵️♂️ Your Barrel Temperature Matters In Affecting The Barrel Vibration and Velocity (Velocity Node and Velocity Changes From That Node, for Accuracy)! 🎯 As you know, from your first "cold bore shot", the point of impact always shifts - once the barrel is heated and you take your second shot! 😳
RE: First Proposition, there are bushings or as you spoke of at 39:50 a "shim" / sleeve which convert a Large primer pocket to accept small primers. I have several on hand for future testing. In addition I have better (lower standard Deviation & E.S.) performance using Large Pistol primers in Large Rifle Primer cartridges when shooting black powder. In addition I use a over primer news print disk inside the case to reduce the brisance. For some reason this really helps to reduce the S.D. and E.S.
I’m working up a load with 6.5 creed with the small rifle primers now. This was a great video and super great info. I have not seen much change in my impact shift when using Hornady powder. Shooting 140grn projectiles. And no over pressure signs. 100 round shot at this point.
Loved both episodes. In this one, at about 39:43 a thought provoking idea is offered with this caveat- "here comes the potentially dumb question"... Of all the discussion, this one sat me up in my chair. Why not? Ok, "now hear me out", is it even plausible, not just possible, to go to the trouble to create inserts to convert brass over to small primer pockets? What are the pros and cons? Much of them were discussed. Here are a couple of mine: 1. Keeping tension/friction on the insert so it captures the primer but allows it to be de-primed after firing, while being retained in the brass. 2. Is easy to insert, perhaps by using a common large primer tool. If the only con is complexity, take a look at re-using military brass. You know, the ones with primer crimps. I don't know anyone who enjoys swaging primer pockets. BUT, if there were a conversion insert designed to easily fit that crimped pocket while locking into the brass, voila!, we can now have high quality, small primer brass that is easy to work. I'm thinking the insert could be designed similar to "0" tolerance piston rings. That would allow them to shrink down to crimp size during insertion, then once past the crimp, open up fully, locked in by the crimp. There would obviously need to be a rim for the shallower small primers to seat on.
Those military crimps are easy. In a single press if u just turn the brass as u start the primer in loading on the press they’ll go in ok. Otherwise a Phillips bit spun in the primer pocket for a sec bevels it enough to load em easy. Military crimps are not a big deal. Even an old drill bit hand spun will bevel em also.
Here is a curve ball for you, remember there are primer pockets with large ignition hole and there are primerpockets with small hole , or even Russian 762.39 has no anvil in their primer and has 2 holes offset in their brass primer hole. .....
I’ve loaded converted berdan to boxer brass. I’ve shot em with nasty big and odd shaped flash Holes. I’m convinced they’re not a big deal. Not for normal shooting I’ve not been able to see anything noticeable. Aslong as the charge is burning and reaching the pressure it doesn’t matter that’s what it’s all about lighting em off and getting the burn to pressure. If they hit the pressure the powder burns. If you’re not a top level bench rest shooter it doesn’t matter.
If you really want to try water cooling a rifle. A pc water cooling company called Barrow makes a 240mm radiator with integrated pump & flush mounted fans. Instead of making a clamp on cooler. I would suggest ordering a barrel with full water cooling sleeve from a company that makes integrally suppressed barrels. A water cooling sleeve or jacket is basically a suppressor without baffles that is sealed to the barrel with viton orings. Have them thread the sleeve for two G1/4 BSP fittings & you can use standard pc water cooling fittings/tube. Would still have to fabricate the stock & battery pack.
outstanding work brother! FYI in ww2 Snipers would keep ammo in their pockets (body heat) to stay warm for cold bore long sits!! who knows.. ALSO loving 6.5 GRENDEL with small rifle pockets... thank goodnes
If you are hunting in freezing temperatures you dont wipe the frost from the case of your second shot when the 1st shot warmed the barrel. Thanks for the dive down another rabbit hole. Im glad my rifle shoots factory ammo well.
During my online searching and snooping off reload equipment and consumables, I’ve come across “shims” or “adapters”, if you will, that will allow you to use either a small or larger rifle primer (don’t recall which one) instead of a 209 style shotgun primer.
I just got my small primer match .308 Starline Brass and loaded up 30 of my subsonic loads using the Hornady 175 gr. Sub-X to go about 1100fps and loaded 30 of my Nosler 168 gr. Accubond LR going about 2390fps. I will see how they compare to my large primer variance.
As a follow-up, I did have tremendous luck with the subsonics, but the ww primers I chose were very soft and the high velocity loads immediately even with low pressure loads extruded into the firing pin hole, so I had to stop that testing and will be unloading those and putting in CCI small rifle instead. I'm hoping that with the harder CCI small rifle or small rifle magnum it will improve this.
For your frost and moisture problem maybe try coating them with WD-40 before or shortly after the cooling process. It worked for NASA and maybe orientating the ammunition up so you only have to touch the bullet as to not transfer any more heat than possible.
Bronze is a poor conductor as long as the primer is not touched. The primer & powder should be hard frozen for at least 1-3 minutes. Powder & primer compound are continuously improving. Even the same compound is being made to a higher more consistent standard. For nearly everyone small verses large primer is a rabbit hole with little value.
I would love to see a 10(20) minute talk on thoughts of all the short action magnums.,(wsm vs saum, vs rcm, maybe prc). Just getting a custom 300 saum built.. more room for freebore than 300wsm
The CCI military large rifle primer does not work very good in bolt action rifles. We got a bunch of military surplus 308 ammo and ran them through our match guns with countless failures to fire then we bought 1,000 CCI military large rifle primers and loaded them for 6.5 creedmoor with H4350 powder and Hornady 140 eld-m and the firing pin constantly pierced the primer. But all of this is in match settings
Would like to see this test with a magnum cartridge 6.5 PRC, 7PRC, 7 Rem Mag, or the like. Would the larger charge weight give a larger variance with the different primers? Great test.
To do this perfectly it would take so long. Cuz you would have to shoot 1 round outa a cold rifle. Put it back in freezer machine and let it fully get cold again , on and on ect. It would take a month of Sundays. But it can be done.
From the outside looking in I'm finding it hard to believe that temperature is the issue. NATO uses small and large rifle primers in their respective cartridges, and military ammo is expected to operate anywhere a person can. From the Siberian winter to Kabul summers. If small primers couldn't work reliably we never wouldve gone to a small rifle primer cartridge like 5.56.
I see an issue with your very cold ammunition test. going into a warm barrel you're gonna get a lot more expansion on the case. which is gonna lower the pressure of the ammunition. because the case is going to expand to fill the chamber. more so than if the gun and the ammunition were at the same ambient temperature. It would be the same for both small and large primer ammunition. but still you would be Getting abnormal reading because of that case expanding so much more in the warm chamber.
😉 Yes, Mark, You Are Right - Use a Temperature Stable Powder for the Experiment! 👨🔬 I would personally like it to be H4831SC, out of a 270 Winchester! 🤑
🤪 I am going to comment before watching this video (only this time) because I want to make sure that my comments are heard/addressed! 🕵️♂️ I Want to Know HOW You Addressed Primer Seating Depth, Primer Crush Amounts, and Powder Variation (Energy Generated) as a Function of Both Temperature and Powder Charge Size/Type (i.e. Powder Column Size and Shape and Available Energy, Powder Volume Amounts, Case Size Variations and Case Demention Variations, Variations in Pressure Measurements and Pressure Values, etc...)? Their are Lots of Variables to Consider and for Used Brass (if their were any) - the changes in primer pocket size from being previously shot, deburring the primer pocket for reuse, case stretch, etc..! Were All of these Variables Measured and Accounted For in Your Experiments? If Not, then How Would that Effect Your Conclusions and the Validity of them? 🤔
Mark, two things... Your openers are amazing. The best part of them is Ryan and Jims reactions. 😂😂. 2nd.... The whole Toyota Tacoma thing that always gets brought up. You are from Washington State, how in the world are you not on the Toyota band wagon.
Have you been keeping Jimmy down in the basement? He’s pretty pale for mid summer. Is that why he’s been off the air or has he just been off at unicorn conventions.
HELP!! When reloading Is it safe to use a Large Rifle Magnun primer on a 30 06 with the H4350 powder or should i try small rifle primer? Can't find any Large Rifle primers? Thank you for you content
where are you finding small primer 30-06 brass? lol . Yes you can load 30-06 with magnum primers just drop your load by 5% and work up the load till you start to see pressure signs. If you don't have large rifle magnum primers already good luck finding them or get ready to pay through the nose for them. They are hard to get and not cheap if you can find them.
Is it just me, or is Jim just a grump? Maybe he doesn't like Mark? I love Mark -- seems like a down to earth, very likable buy. And then there's the professor....Dr. Muck...
