Primer test

[spudgun]

I read a article in shooting times about primers and the effect they can have on your loads.
So I figured that I would test the different small rifle primers I have on the shelf.

I normally use the CCI 400 primer with 40.6gr H4350, Hornady 105 match bullet. This load usually gives me a 6-7" group at 1k. Would have done it this time but I pulled on shot #1 and it went into the 7 ring. The rest were all within .5 MOA.

Have been using the above load for 2 years now.

6mm CM, FPS at 1000 yds.

SHOT		#1	#2	#3	#4	#5	#6	#7	AVG	SD	GRP "
WINCHESTER	​	1365.0​	1340.0​	1324.0​	1328.0​	1336.0​	1338.0​	1294.0​	1332.1​	15.9​	19.5
CCI 450 MAG	​	1342.0​	1317.0​	1323.0​	1343.0​	1359.0​	1311.0​	1312.0​	1329.6​	18.5​	18.5
CCI 400		1331.0​	1320.0​	1328.0​	1319.0​	1346.0​	1345.0​	1320.0​	1329.9​	9.6​	11.3​
CCI #41		1327.0​	1351.0​	1344.0​	1305.0​	1368.0​	1339.0​	0​	1339.0​	22.8​	17.7​
FED 205M	​	1296.0​	1285.0​	1346.0​	1311.0​	1329.0​	12880.​	0​	1307.8​	24.6​	14.3

What suprised me was the Fed 205M Match primers. They were 25-30 FPS slower.

Also the SD has me a little puzzled... Not sure what to make of it since the high spread.

 

[Doom]

Spudgun,

I'm not sure exactly how you posted the data but because my mean/SD for the 205M is a little different than yours. That said, when I use your data, assuming 1323 for #5 and and analyze the standard deviations statistically, the difference between CCI 400 and F205M is not statistically different. You would need to collect significantly more data to make that determination.

 

[CharlieNC]

Spudgun,

I'm not sure exactly how you posted the data but because my mean/SD for the 205M is a little different than yours. That said, when I use your data, assuming 1323 for #5 and and analyze the standard deviations statistically, the difference between CCI 400 and F205M is not statistically different. You would need to collect significantly more data to make that determination.

But the sd is different at 95%, which is more meaningful to me.

 

[Doom]

Spudgun,

When doing the comparison between the tests you have to considerer probabilities. This is where analysis of variance (ANOVA) comes in. While you may make decisions on the raw test data that is not how it should be analyzed.

It is highly likely that if you were to run the same test again the results would be different.

 

[lawman29]

When I use a chronograph it is to measure:
1) Velocity
2) E.S. (looking for 20 or less)

 

[darkangel_r2]

I know this test isn't designed to say which primers is better overall as it is likely that every primer likes a slightly different powder charge. Still interesting to see the results though. 205m being that cold and cci450s not making a difference for average velocity is surprising. Does a 450 have more priming compound or is it just a thicker cup?

So I have a question. How would you reliably quantify which primer is truly the best for a powder and bullet combo? Average accuracy of each charge level during load dev? Average es/sd #s? Most accurate load? Widest node? Thoughts?

 

[spudgun]

Well, this data was taken off the Silver Mountian software that we use at the shooting range.

I did not use a crono on these shots just took info off the screen when the shooing was finished.

How accurate is the data, well can't say as I had no way to double check the FPS and SD.

I only did this test to see just what different primers I had in stock would do if I needed to change them.

If and when I run out of the CCI400 and am forced to use another I would go through the ladder testing to see just what that primer, powder would like with my setup.

I am happy with the CCI 400 that I have been using but my supply will be running low soon if they get hard to find.

Just posted this to give my results not to say which one is better.

I do like the comments though. I can always learn something with others inputs.

 

[Doom]

The results differs due to data rounding. I actually found the test interesting. One of the things that I have been curious about is how much difference there may be between #41 and 450s and from your testing it’s not much.

 

[NV_Dmax]

Is GRP your group size at 1000yds?

 

[spudgun]

Is GRP your group size at 1000yds?

Yes, in inches.

 

[bks22345]

When I first started reloading I read some articles about pierced primers in ARs using CCI 400, so I bought a bunch of 205M. Recently I was working loads for my 6.5 Grendel and decided to try the 400s in my “best” 205 load. Nothing scientific but shooting the two back to back, the 400s were tighter. Take it for what it’s worth, but all my AR loads are now with CCI 400s.

 

[David Christian]

@spudgun, thanks for posting your test. Imo, if I wanted to get more tangible information from comparing different primers, I would need to work up independent powder ladders with each primer. I would not be able to use the same powder charge across each primer as they may have different burn times and different levels of energy. I would also normally only compare 2 primers at a time.

 

[mikecr]

Seems like your difference came down to what you load developed with.
And if you needed to use another primer, you should at least powder develop again.

I think the abstract in this is not actually the primers, but local striking of them.
I suspect that primer striking can be optimized for a given primer, as seating can be optimized for a given bullet.
So maybe your striking is not optimum for ANY of the primers tested, but your powder development is countering a bit for the primer in use. This, making it appear like CCI400 is magically better, but that might not be true at all.
It could actually be that the Fed205M locks in a best result, with a 20thou backing off of released firing pin, and revisiting powder development. You just don't know

 

[JFrank]

@spudgun, thanks for posting your test. Imo, if I wanted to get more tangible information from comparing different primers, I would need to work up independent powder ladders with each primer. I would not be able to use the same powder charge across each primer as they may have different burn times and different levels of energy. I would also normally only compare 2 primers at a time.

I don't always test primers, but when I do...This is the way forward.

 

[Ned Ludd]

@spudgun, thanks for posting your test. Imo, if I wanted to get more tangible information from comparing different primers, I would need to work up independent powder ladders with each primer. I would not be able to use the same powder charge across each primer as they may have different burn times and different levels of energy. I would also normally only compare 2 primers at a time.

David - I think the real question some might ask that do not ordinarily test different primers, or that only might do it on rare occasions is, "Can any benefit of a using different primer in terms of ES/SD be observed in between accuracy nodes, i.e. an un-tuned load, or only when the load is "in the window", i.e. an optimized load?" Obviously, this question would be less for those that are [relatively] uninterested in velocity data and use some other readout when testing primers, such as precision.

I cannot think of a good reason why one primer that produces lower ES/SD as compared to others would not do so at velocities across a wide range of charge weights. Sure, the ES/SD values may increase outside of the node, but one might expect they should increase proportionally for any primer tested outside the node. If the ES/SD values increase even remotely proportionally outside the "optimal window" for all the primers tested, the primer that produced the lower ES/SD value should still be identifiable relative to the others tested. If the best primer for a given load could be identified using ES/SD values even if the charge weight was not optimal, it would save a lot of time and effort in the testing process, as well as minimize the round count on a barrel. Nonetheless, I know a number of very good F-Class shooters that test/compare primers only using fully-developed loads with each primer.

I think that there are some reloaders that might like to test different primers more often, but perhaps don't because of the potential cost in terms of reloading components and barrel life if the load must be optimized first with each primer before a valid comparison can be made. It is sometimes difficult to explain to others how/why two primers might give very different ES/SD results, but only within an optimal load window as developed separately with each primer, because I don't really have a good explanation for why that would happen.

 

[whatsupdoc]

Looking at all this, I have a few thoughts (oh noooooo Mr Bill).

First, I wonder how accurate the chronograph numbers are, I believe the chronograph is acoustic and
not sure how accurate the numbers are. No clue.

Second, being that no two bullets are truly the same, could some numbers be skewed by the
small BC differences between the bullets.

I am thinking that if you take speed readings at the muzzle you are clocking only the pure load variance
but at 1K you are now clocking load variance and bullet BC variance.

 

[NV_Dmax]

this is where I was headed next after my question about the group sizing.

@spudgun, thanks for posting your test. Imo, if I wanted to get more tangible information from comparing different primers, I would need to work up independent powder ladders with each primer. I would not be able to use the same powder charge across each primer as they may have different burn times and different levels of energy. I would also normally only compare 2 primers at a time.

 

[JimSC]

If you developed the load using a certain bullet, case, powder, and primer it does not surprise me that when you change any of the components the data will change to some degree. I would wager you could take anyone of those primers and massage the seating depth or powder charge slightly and end up with comparable groups sizes and SD numbers for that particular primer

 

[spudgun]

Wow, I kinda wish I never posted the results.

Ok, for all those expert reloaders.

1. I only did this primer test because I read a article in Shooting times that kinda did the same thing for fun to see if my results were close to there results.

2. Yes the FPS is measured at the target via acoustic sound. So how accurate is it really. I have no way to tell. Each bullet no matter what it's BC value should not change the noise signature. Might have some slight effect of the FPS it is traveling. So I dont take the FPS as true (maybe yes or maybe no) I do know what my FPS is at the muzzle is as I do crono each load development and look for the node.

3. Sine at this time I don't need to change primers because I do have a supply of CCI400 that will last me through the year and into the next.

4. Yes there may be a time that I will need to change primers and if that time comes I will do my load development as I have many times in the past when changing powder, bullet manufacture, jump, barrel etc.

5. I had no intention as to try to tell the world which primer is good or bad only posted my results for reference based on my load (40.6, H4350, 105 Hornady match) when only 1 variable was changed.

Everyone has a way to get the performance out of there pet loads. I have mine and you have yours. My way might be backwards to yours but the end results may be the same. I am satisfied
with my shooting at both 600 and 1000 yds. If something goes awry and groups open up then I can look at the gun and not the load (as it has not changed). Most of the time it can be traced to bedding, barrel erosion or just time to clean it (usually around 300 rnds). I'm on my 3rd barrels on both guns. My gun is not a custom $5k gun, but one that I have put together and worked on my self.

My 6 and 7" groups at 1k (6mm and 6.5CM) didn't happen overnight. Been doing this for 3 years. I feel good after a 600 and 1K shoot as I think I can hang in with the light gun class.

Thank you experts for your understanding

 

[JimSC]

I have done similar tests at the end of doing a load development and found that a different primer gave me better results. One that popped to mind was this .260 Rem load, Sierra 120 SMK's, and Varget. I did the powder workup, then the seating depth using CCI 400's and had a acceptable results but when I tested the load with three other primers found that Federal GM's improved the group size and ES/SD numbers.

I honestly thought from your original post that was why you had ran the test. If you are really curious why not pick one of the other primers and do some minor tweaking to the load and see what happens.