Home Forums Reloading Varmint Rifles flash holes in brass

I loaded up 25 more rounds with 24.4 grains of 3031 and I found my CCI 400 primers. I had one more sleeve left. Now I have the ammo I loaded in 2019 with the undrilled primer holes and the ammo I loaded today with the drilled primer holes. Although the brass will be mixed but it is mostly 5.56 Lake City and 5.56 Winchester. I won't have the third party. It will just be me. It will be next week before I get to shoot them. Our local range is muy busy on the weekends.

kwg

Working over some 22 Hornet brass today and had a few that were hard to de-prime because the hole was smaller.

Used my flash hole tool from the inside to open them up.

My Lyman primer hole tool is .076" at it's widest point.

kwg

"uniforming" to what extent? I've never drilled out each individual flash hole. It is unnecessary. A lot of guys are searching for some magic cure to their inaccuracy problems. A little hint here, make sure there is no burr and that they are centered and fairly uniform in size. They don't have to be 3mm in size. There's a reason SAMMI spec is there. If they say a .076-.082" flash hole is acceptable (and it is), then go with it. If there was some magic in a huge flash hole, I guarantee people like Lapua would be on top of it, yet they abide by SAMMI specifications. If you guys are not producing sub moa ammo, something is wrong with your loading process, load work up process, skill or shooting technique/marksmanship (or lack thereof) or your rifle. Not because the flash hole is the wrong size. If you are unhappy with your LC brass, buy Lapua. OP, are you loading for benchrest competitions? What kind of rifle are you shooting this 223 ammo in? What kind of accuracy are you getting right now with your handloads? I'm talking consistent accuracy. 5 shot groups are almost a joke for any 223 rem. 10 shots is a better indication of what a rifle and shooter can do. I'd also take heed in what swifty52 said about drilling the flash hole too big. You could actually do some damage to your rifle, by doing this.

BSA,
You are right. I have tweaked brass many times primer pockets, deburred flash holes etc. but never enlarged the flash hole as it seems to be a complete waste of time. Where I think the OP is headed is down a rabbit hole that doesn’t lead to wonderland. Not once has he given a baseline in velocity.
Velocity = pressure just because all of a sudden a Mini14 and AR which are known to have generous chamber dimensions start chucking brass different doesn’t tell me a damn thing. I can say the same about my AR’s as I use a brass catcher. All go into a neat little pile in the bag. 😀 Did pressure go up or down? Sounds like down as it degassed his semi autos.
Whether it’s 5 shot or 10 shot groups the goal is the same shoot into one small hole. I usually run two 5 shot groups and chronograph with a 35P. I very rarely shoot the bullseye since I was taught to never shoot out your aiming point. When that’s gone you have to guess where in that hole to hold.
Also using wind as a reason for sh*t groups is no excuse. The OP sounds like he doesn’t know how to use wind flags, you shoot the conditions, waiting for a lull in winds to shoot a calm condition can be another exercise in futility.
Pick a single flag position that puts your sighters where you want them 10 ring for score or wherever on the scoring target for group and then shoot the same exact condition. A lot of times shooting full value is easier.

I applaud the OP’s efforts, but my opinion is he’s pissing in the wind.

Amen buddy. Great post.

There are a few making custom brass that use smaller than normal flash hole diameters, RMC for example. They are sufficiently small that a standard decapping pin will not fit.

Certain Lapua offerings have small flash holes too.

Lapua and others make small rifle primer brass with smaller diameter flash holes. They require a .059 pin if I remember correctly.

This looks like another test invalidating variable.

Agree .059 pin, 1.6mm = .063 so 4 thou smaller sounds about right.

Exactly

You guys are right, too many variables. I have to come up with a better plan. I don't have a chrono so there is no checking speed. As for the wind and the flag, I did the best I could with what I had. I was using a club range so there was no setting it up to my liking. Since I was by myself I didn't have someone to check the wind for me. This is a low budget project with limited resources. I'm doing the best I can with what I have. The results may be inconclusive .

kwg

I can’t cure your lack of chronograph but with the wind flags there are alternatives.
1. Get or make a 24-36” garden stake. Around here the plastic ones go for about 2 bucks.
2. Surveyors tape any color. Price on that has jumped quite a bit since I bought. About 7 bucks for 100 ft.
3. Tie a 1.5 - 2ft. Piece of tape to the stake or whatever length you want. Place the stake in a position and height where you can see it through the scope but doesn’t obscure your target. You now have a crude but visible wind flag. Make up different heights or as many as you want and place them at different yardages. Crude but effective.

I can’t help with the stakes but if needed send me your address by PM and I will send you a roll of surveyors tape at no cost to you.
Again I applaud your efforts but you gotta understand that we can be a very critical audience.

Hello Swifty
I can come up with something to hang next to my target when I go out the next time to check the wind. Our range faces due east and the last time I shot we had a strong wind out of the south. We also have a burm on the south edge of the range and the wind does all kinds of weird things once it clears the burm. It is what it is. I didn't expect MOA accuracy with the way the wind was blowing and I sure as heck didn't get it. A chrono would be nice but I have other needs for the cash. It's just a little further down the list of "must haves". The new radar chrono's have really gotten my attention but the money is not there.

When I started this my primary learning concern was; is pressure coming back through the primer hole ?. I have noticed that the CCI 400's seem to have either a softer or thinner cup than the CCI 450's and the Federal Match primers I have been shooting. I punctured 3 primers the last time I was out with the CCI 400's. I have punctured some on other rifles in the past. That is why I don't have but just a few left. I don't trust them especially with fast burning powder. When I get done with this batch I will go to the Winchester small rifle primers and pretty much start over. I should have some of the bugs (variables) worked out of the process by then.

Accuracy was and is my secondary concern but I am interested in seeing if there is an improvement. If I start puncturing primers with the .086 holed brass I'll stop post haste before I break something. If I don't break anything I'll try a slightly larger hole. I don't know if I will reach a 3mm hole. That's a pretty big hole. The study as presented by NVhnter claims up to a 28% improvement in accuracy. That's a huge claim but he had several learned fellows guiding him through the project so I am not going to doubt his word. I would settle for just a fraction of that percent.

I'm scrounging through my brass now to find something that is all matching so I can eliminate the brass variable. As for primers, during times like this CCI 400's may be the only thing on the shelf. I want to know what their limitations are and what I can do to mitigate the limitations. The other learning objective is, am I wasting my time making the holes in brass uniform in size?? Based on what I read above some folks apparently think it's worth the time and others are not doing it. We shall see.

kwg

The Speer loading manuals used to address how to use their plastic bullets in normal brass cases vs. their special plastic cases you would normally use. If I remember correctly it said you could drill out the flash holes of brass cases and using primers only, fire the plastic bullets for practice.
There was also a warning about NOT using those cases with drilled out flash holes for normal loads because the larger the flash hole, the more pressure permitted into the primer. This may be what you’re running into with the blown primers.

Here you go:
Speer maanual #13, pg 596…
“The Target-45 system is slightly different from the 38 and 44 versions. T-45 bullets are used in standard brass 45 Auto cases. Bullets are pressed into a primed, resized case with finger pressure until they stop. If primer setback occurs, open the flash hole with a 7/64” drill. Do not use these modified cases for conventional loading. Mark them with a bright, permanent color or notch the rims with a file to clearly identify them as practice cases.”

kwg,
To be clear, I had no personal involvement in the masters thesis on primer holes that I provided the link to. Just something I came across online that I found interesting and pertinent to your original post.

I would also suggest that unless your Mini-14 has been upgraded to improve it's accuracy you are wasting your time looking for improvement there. Unless yours is one of the newer target models, Minis are just not accuracy rifles. Stick to testing with your AR.

Hello NVhntr

I understand. It is a great article. Duplicating the results may be difficult. As for the Mini 14 I wanted to see if I was going to get any pierced primers. I have had them using the CCI #400's and firing them through the Mini. Like I said before, I was surprised by how the brass piled in one spot . I don't know if it was a fluke or drilling the primer hole to .086 had anything to do with it. I'm currently setting up to use my Ruger American .223 compact. It's easier to keep track of the brass than with an AR. Rain tonight, windy tomorrow with a cold front moving in and hopefully by Wednesday I can have better conditions to go try these loads.

kwg

I made it back to the range today. The wind was out of the northwest at about 8 to 10 mph and 70 degrees. It was Great shooting weather. I couldn't get on to the 100 yard range today so I had to settle for the 50. That's OK because I was working on shooting technique and getting the torque on the stock bolts adjusted to where the rifle liked it.

I pulled the barreled receiver from the stock after my last range session because one side of the stock was touching the barrel. I sanded down the offending side and put it all back together. I finally adjusted the rear Allen screw to 10-12 foot lbs of torque and the front to 6 to 8 lbs of torque while I was at the rage today. This is a SWAG based on my years in the National Guard torquing nuts on a Huey. What ever the number, I finally got it to what seems to be the sweet spot.

It turns out the brass I had drilled out to .086 shot the best 2 groups at .650". I drilled out the flash hole on 10 pieces of brass to .093. (2.36 mm) I did not see an improvement in accuracy but I only found a slight visible splash at the primer hole. So, at that flash hole dimension there does not seem to be a pressure issue. The best group for the brass drilled to .093 brass was .730. The same number as the factory hole.

It was mentioned to eliminate variables.
So, yesterday I started digging through about 3000 twice fired pieces of brass looking for nothing but Lake City brass. I think I have found enough LC17 to put together about 100 rounds of ammo with various hole dimensions. The smallest being the factory hole. I have not yet decided what the largest hole will be . Like I said, I did drill out 10 pieces of brass to .093 today and shot it at the 50 yard range. I did not get an accuracy increase. I just know there didn't seem to be any excessive pressure issues that I could find looking at the brass and the primer.

After doing a little math based on IMR's numbers 24.4 grains of 3031 delivers 52,073 lbs of pressure at the chamber.

kwg

Yesterday, while randomly picking up and inspecting once fired WW brass, I found part of the breakout from the flashhole being punched out folded back over the flashhole and obscuring part of it. Doesn't happen often but I have seen that in the past. And that's the biggest reason I uniform flashholes, especially for brass that has the hole punched.

My Lapua brass on the other hand, I don't think a guy can improve on the flashholes......