Primer testing

H

hounddawg

New member
a small test of 4 different small rifle primers. I only did 10 shots per primer except for the CCI 400, one of which had a squib. A 15 or 20 shot group would be preferable but this gave me a idea of what worked for this load. I used Peterson .260 Rem SR cases on their 3rd firing. They were wet tumbled, annealed, trimmed to 2.030, chamfered and deburred. Sized on a Redding type S with a .291 bushing for .003 neck tension. Bullets were 120 SMK's seated .025 from lands at 2.293 inches. Powder was 36.2 gns of Varget which is a very low load for this cartridge and bullet. Gun is a Savage 10 action with a 24 inch Criterion 1 - 8 twist barrel set up as a tactical with MDT chassis and Magpul buttstock shot from a bipod and a rear bag.


It is pretty obvious the best group was # 3, the Federal GM match primers and also odd that the #4 group the CCI 450's had the lowest SD yet was all over the target. I would run the test again using 3 groups of 5 each primer except am not going to mess with this load much more. The velocity is acceptable for up to 600 yards but groups would fall apart at 800 or 1000 due to the low velocity

Code: 
Primer	    Velocity     ES	SD	Mean Radius																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																											
																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																															
CCI 400    	2627	31	11	0.326																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																											
Remington 7 ½	2651	37	12	0.431																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																											
Federal GM      2647	21	7	0.236																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																																											
CCI 450	        2645	15	5	0.339


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I brought your image down to a size that fits most screens.

I'll stick my neck out and guess the Federal primer produced a better barrel time or else that initial ignition was quicker due to the higher sensitivity of the Federal primer, allowing less time for mechanical vibration to affect the muzzle position. It would take rigging some special instrumentation to tell.
 
Thanks Nick, I use a monster monitor so I have a hard time judging image size.


This is my practice gun so as long as it shoots good at 300 and 600 I may just stay with that load. I will redo the CCI 450 with at least a 15 shot group, that group should have been better with that low SD and ES. Plus I only have part of a flat of Feds left and a ton of CCI 450's.

I shot these using the muzzle break. I am not sure how that would affect the groups but it allows me to concentrate on wind rather than recoil
 
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It would be interesting to see what an Audette ladder or an OCW round robin would look like for those loads to learn if it's a change of barrel timing or not.

In general, if you limit photo width to 800 pixels, it will do fine on all screens. A decade ago I would have said 640 pixels. Today nobody has screens with resolution that low, and you'd be fine with 1080 on most machines, and I wouldn't bother to change that.

There are lots of free apps that will let you change it by pixel. Infranview is a photo editor that is one.
 
Long Story about that load. I actually developed it on another barrel a couple of years back. It shot consistent .3 to .5 and since I was shooting mostly at 100 and 200 the velocity was a moot point. The Hogdon site started me at 36.0 and when I started seeing sub .5 MOA groups consistently at 36.2 I called it good. When I started breaking this barrel in I had some of these loaded in a Lapua cases with a large rifle primer and they shot sub MOA out to 600 so I have never really done any real load development on this barrel.

I may do a quick run up to 39.0 someday to see if I can get the velocity up to 2850. But as of right now I have it set up as a precision rifle and not a F class gun. I did use it in a mid range match with the brake removed and did well with it. However it gave my shoulder a workout after 60 shots since it has almost no weight and brakes are not allowed in competition.

With the brake on and 120 gn bullets shooting a mild load there is almost no recoil. For right now I think I will just keep the load as is other than maybe do some seating length tests and use it to bang steel
 
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I did something similar a few years back with all of the primers limited to CCI and ten shot groups. Unfortunately I was more focused with getting the shots over the chronograph than group size on the target. All of the below images are mine and I am linking my images to a domain which I own. Anyone is welcome to any of this data.

Primer%20Test%201.png


The chronograph data dumped into a spreadsheet:
CCI%20Primer%20Test%201.png


The 100 yard target:
223%20Primer%20Test.png


All of the brass, LC 11, was sized identical. All of the powder charges were individually weighed and the only difference was the primers used. The load data is on the images. The CCI #41, mil-spec magnum primers did yield slightly higher velocity average and the CCI BR (Bench Rest) primers did yield the best standard deviation. I think I actually still have the remaining 15 rounds from each batch so maybe this summer I'll get out there and focus more on the target this time. :)

Ron
 
It is hard running these tests, I screwed up by shooting the wrong end of the line this morning and not taking the wind direction into consideration. The tree line generates a lot of turbulence on that side of the line with a SW wind. I knew that but just did not think when I set up, once the wind flags were in position and the line went hot I kicked myself in the keister and shot anyway trying to read the flags

Still the tests are fun and a learning experience. I had picked up a few sleeves of Rem 7.5's for a .223 load with with a CFE 223 for my .223 that a friend swears shoots bug holes at 200. Maybe next week that .223 may head to the range for some action

here is the extended target data for the entire 39 shots. The CEP numbers are still decent considering the 4 different primers used. I would like to trim .2 off that 95% number and .1 off the SD radius and I would be very happy to shoot that load at 600.


mytcRnL.jpg
 
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That reminds me the day I shot what I posted there was little wind, negligible and the outside air temp was about 70 F. I have some .308 Winchester brass I need to charge and shoot this spring. Talking shooting at at the moment they are predicting possible snow next week here in NE, Ohio. Been pretty much cold and when we see a 50 degree day it's raining. Anyway, I agree that making up loads and getting data is fun as well as interesting. The .308 science experiment is more about case volume than primers so I'll see what happens.

Ron
 
make sure you do a thread on them. I am a numbers geek and always enjoy learning. Condolences on the weather. I won't rub in what a nice 70 degree day we had here on the SE coast
 
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