Another 10mm question

[Boriqua]

I was using Winchester large primers for my 10mm reloads but am just about out. I switched over to cci for my small pistol primer needs and like them a bit better than the winchester. If I get cci large pistol primers for 10mm should I get magnum or standard?

The Winchester I have been using says for both magnum and standard loads.

So #300 or #350?
Alex

 

[Suck My Glock]

On the small capacity case of the 10mm, standards will be just fine.

 

[Boriqua]

On the small capacity case of the 10mm, standards will be just fine.

Awesome! Than kyou. I think they are a couple bucks cheaper too .. not enough to have swayed my decision but cool none the less!

I found with the small CCI primers, and it could be me, that they go into the pocket so much smoother than the winchesters. I am using the little flip out primer tool on a lee classic press but the difference is night and day. They just seem more uniform so I figured if I liked them that much in the small primers that I would buy a couple hundred of the CCI large primers and see if I like them better as well.

 

[Flash]

Magnum primers are only required with hard to ignite powders and subzero shooting conditions.

 

[Elk34]

That will be personal preference.

 

[Boriqua]

Yes because so much of what I have been learning about reloading is about "feels" and not verifiable things like pressure.

 

[Elk34]

Yes your right it's all about how it feels

 

[jls in az]

The biggest difference between "magnum" and "standard" primers is the thickness of the base. Magnum loads require a thicker base on the primer to handle the extra pressure.

 

[shooter444]

When I wanted a little more oomph, from my maximum Trail Boss loads, I found recommendations that 'mag primers' could be used, for that purpose. But, I didn't notice all that much of a difference.

Further research found that, any load/powder can be switched to 'mag primers' if started with a 10% reduction in powder, and then worked up, watching for negative signs.

I also read where some guys were opening up the flash hole, when switching to 'mag primers',... but, this is all Internet Info,... to be taken with a grain of salt, imo.

 

[Jack Dupp]

I'd say it depends on which powder you're using.

 

[Flash]

I'd say it depends on which powder you're using.

And you'd be right.

Opening up the flash hole is what you do when you want to shoot wax loads to practice your quick draw cowboy action shooting.

 

[shooter444]

Agreed, and, it is also a well studied process, for those who like to tweak things,... this link takes awhile to load,...

https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=8415&context=masters_theses

"The effects of physical flash hole deviations on factory-grade rifle ammunition

Nicolaas Martin Schrier
Keywords and Phrases
Flash hole

Abstract
"The objective of this research is to determine the effect of dimensional and positional changes of the primer flash hole on the performance of factory-grade rifle ammunition. The studied variables were flash hole diameter, offset from center, and orientation of the offset in the primer pocket. Cartridge performance was quantified by measuring muzzle velocity, chamber pressure, and target grouping size (precision).

Five different flash hole diameters were tested for both the Remington .223 and Winchester .308 calibers: 1.4mm, 2.0mm (the Fiocchi standard), 2.4mm, 2.8mm, and 3.0mm. Each diameter was tested at three offsets: centered (no offset), 0.5mm from center, and 1.0mm from center. Each of the 0.5mm and 1.0mm offsets were tested at three orientations: up (12 O'clock), side (3 O'clock), and down (6 O'clock). Every flash hole was manually drilled and each cartridge hand-loaded in order to conduct controlled testing of the flash hole variations. Testing took place in two segments with the muzzle velocity and precision measured at a private range outside Rolla, MO and chamber pressure and a second muzzle velocity measured at Fiocchi of America (Ozark, MO).

Results showed that muzzle velocity and chamber pressure varied 1-4% from the control flash hole as hole diameter, offset, and orientation changed. The precision, particularly in the 3mm diameter and centered flash hole cases resulted in improvements of up to 28%. Variations in flash hole diameter, offset, and orientation do affect cartridge performance. Alternate flash hole diameters exist that improve powder ignition consistently as well as precision. Off centered flash holes increase target grouping size and result in less consistent muzzle velocity and chamber pressure values."--Abstract, page iii.

Advisor(s)
Worsey, Paul Nicholas

Committee Member(s)
Worsey, Gillian M.
Baird, Jason, 1955-

Department(s)
Mining and Nuclear Engineering

Degree Name
M.S. in Explosives Engineering

Publisher
Missouri University of Science and Technology

Publication Date
Spring 2015"

 

[Elk34]

What reloading book are you using? I believe in there they state what primers they use on the test weapon for each caliber.

 

[Boriqua]

What reloading book are you using? I believe in there they state what primers they use on the test weapon for each caliber.

They do and Hogdon did not call for a magnum primer. Having said that .. its a gun board and there are a couple of guys like Flash whose opinions I respect and I just wanted to see what others were doing. I wish Intel6 played around here because between Him flash and a couple other dudes you have about 1000 years of hands on experience that a quick look in a book wont give me.

If people on a gun board dont ask new questions about guns it may as well be a crappy replacement for backpage and just make it about classifieds.

I am not only interested in making range fodder but learning to be a reloader. For that I need information that isnt on a chart.

There are cooks and there are people who follow recipes .. I want to be a cook.

 

[Elk34]

Well there is some stuff they won't do that I do. I can tell you they don't use onion paper in there cases to keep the powder from going in to the anvil of the primer . Just because someone has been doing something for a long time doesn't mean it right. It just means fate hasn't caught up to them yet. There are thi ts I know about that i will never say to anyone because it's so experimental that i cant trust anyone not to hurt themselves.

 

[Intel6]

I swear I commented on this specific question? Was it on another forum?

Usually LP magnum primers are used when you have a large case full of slow burning powder that you need to get ignited. We are talking large cases like .44 Mag and .45 Colt and larger. When you have those cases filled with slow burning pistol powder like Win 296 or Lil'gun you need the Magnum LP to get it going. The 10mm case does not have the large case volume of the magnum revolver rounds and I don't see why anyone would think they need a LPM primer for the round? I think some people just assume "it has to be better/needed" without any real evidence. In this case more isn't always better.

Many people do not realize that sometimes using primers that are too powerful for the case volume can cause problems. This happens in small capacity rifle rounds like the .22 Hornet. SR primers are made to ignite 20+ grain charges of powder so when they are used in a small cased (small case volume) rounds (around 10 grains of powder) the initial blast unseats the bullet before the powder has been ignited and then the powder ignites. So the bullet gets popped out of the case neck, slows down when it hits the rifling lead and then gets hit by the pressure of the burning powder. So rather than the pressure building and gradually pushing the bullet out of the case, into the rifling and down the barrel it slams into the slowing bullet and has to get it going again. This causes problems with the pressure curve and spikes it. Many people who load small cases like the Hornet have found that using small pistol primers (less powerful) results in much better accuracy. Remington actually makes a small rifle primer (Rem 6 1/2) that is less powerful just for small cased rifle rounds. That is all I use in my small cased rounds like .22 Hornet, .218 Mashbrun Bee and .17 Ackley Hornet.

Anyways, to get back on track:

In the case of the 10mm a lot of experienced 10mm reloaders have found that the CCI LPM primers have caused pressure spikes/problems when working with the high end 10mm loads. As a result it is common practice to use the regular CCI 300. I have standardized on the CCI 300 LP primer for all my 10mm loads and while I do have CCI 350 LPM primers I only use them for my .458 SOCOM loads.

 

[Intel6]

Also wanted to comment on the drilling out of flash holes in cases. The inference is that drilling the flash hole bigger helps with ignition or makes a loaded round more powerful?

I will put this out on its own line to make it clear DO NOT USE CASES WITH DRILLED OUT FLASH HOLES FOR LOADING REGULAR FULL PRESSURE ROUNDS.

Drilling out flash holes is only used in loading extremely low pressure rounds like blanks, wax bullet loads or what are commonly known as "cat sneeze" loads. In these types of rounds the primer backs out because it is trying to get all its combustion pressure out the small flash hole and the back pressure in the primer pocket pushes back on the primer and there is no reward pressure of the cartridge to re-seat it (see below). The primer backing out causes problems with the function of the firearm so you don't want that. The easy solution for these rounds is to drill out the flash hole so the primer pressure flows into the case with no backpressure on the primer and it stays fully seated.

When a loaded round is fired the pressure in the case not only pushes the bullet out the barrel but it also tries to push the case rearwards. Pressure follows the path of least resistance and flows back through the flash hole and tries to push the primer out. Because of the high pressure the whole case pushes back against the breach face sealing against the pressure and the primer stays seated. Realize that the brass case and brass primer are a "system" designed to seal that pressure from going rearward. The primer is sealing against the pressure and that is helped by the small flash hole restricting the pressure it has to deal with. If you open up that flash hole it lets more pressure back through to the primer and that small thin brass cup is the weakest spot in that case/primer "system" so it will be the first to let go.

 

[Boriqua]

Hey Intel6 .. I swear it wasnt me who asked!!
Having said that .. thank you for chiming in! You are one of the guys I always hope to hear from when the subject of making your own ammunition comes up.

I have pulled back from the local boards for the most part because the ratio of Stupid stuff to good useful gun talk and information is skewed the wrong way for me and I will admit to some times being sucked into the stupid void!

Keep posting though as I love to follow along!

 

[Intel6]

I would have sworn it was you, it was the same question, 10mm & magnum primers? Anyway, I am always willing to help out with questions. Especially when someone like you with a genuine interest asks. I have been reloading for 30+ years now and always say if I can cut down someone's learning curve and/or keep them from hurting themselves then I need to do what I can to help.

 

[Flash]

Only 30+ years? You're a newcomer.

At this point I'm at 65 years.

Seriously though, you are one of the few knowledgeable ones. There are a lot of experienced reloaders, been at it a long time, but very few knowledgeable ones.

Boriqua will end up being a knowledgeable one.

BTW, I didn't feel moved to do a complete primer (pun intended) of primers as I've encountered some hostility in the past when doing things like that, but I'm sure some here will end up reading and learning from what you wrote.