How much difference do primers make in velocity?

[jblomenberg16]

Shot some loads I'm working on tonight for my AR. I'm using up some generic, non-labled SR primers that I took on trade. What I've seen thus far is that my velocity is probably a good 100-150 FPS lower on average than I would expect for the load I'm using, especially since its at the top of the maximum book load. I'm also not really seeing the pressure signs I'd expect.


I typically use CCI primers, and CCI BR for my accuracy loads, but have also had good success with Winchesters. Just curious if others with more reloading experience had seen this same kind of variance between primer manufacturers.

 

[sloughfoot]

I am curious about "generic non-labeled SR primers". They had to made by somebody.....?

I find that Winchester primers get things going faster than the Remington 7 1/2 primers that I use for my match ammo. I have found that CCI primers are also milder than Winchester primers. The milder primers seem more consistant than the Winchesters.

The reloading books maximums are nowhere near what they used to be, so I wouldn't worry about that too much.

Unless you are using the exact chamber and barrel that the manual had used, you probably won't get the exact same velocities. As for me, if I am 150 FPS under maximum, I will be happy with a safe and probably accurate load.

 

[need4speed255]

They make a huge difference in velocity when you put them in backwards.

 

[walker]

Lyman 49th Edition, page 57 The variations in primer sizes or types can create substantial variations in ballistic uniformity. Rem 9 1/2 - 2509fps 52,800psi, Fed 210 Match -2508fps 53,100psi, CCI 200 - 2526fps 54,000psi, Win. WLR - 2539fps 54,700psi, CCI 34 - 2545fps 55,400psi TOTAL SPREAD 37fps 2,600psi. The above results were obtained by using the exact same 308 Win. load and only changing the primer. A change in primer will change the ballistics of a load, so we recommend that new reloaders use the exact components listed in our reloading data...

 

[jblomenberg16]

I am curious about "generic non-labeled SR primers". They had to made by somebody.....?

I find that Winchester primers get things going faster than the Remington 7 1/2 primers that I use for my match ammo. I have found that CCI primers are also milder than Winchester primers. The milder primers seem more consistant than the Winchesters.

The reloading books maximums are nowhere near what they used to be, so I wouldn't worry about that too much.

Unless you are using the exact chamber and barrel that the manual had used, you probably won't get the exact same velocities. As for me, if I am 150 FPS under maximum, I will be happy with a safe and probably accurate load.

I'll try to get a picture of the box tonight. Plain white box, with plain white sleeves of 100 primers.

 

[jblomenberg16]

I am curious about "generic non-labeled SR primers". They had to made by somebody.....?

I find that Winchester primers get things going faster than the Remington 7 1/2 primers that I use for my match ammo. I have found that CCI primers are also milder than Winchester primers. The milder primers seem more consistant than the Winchesters.

The reloading books maximums are nowhere near what they used to be, so I wouldn't worry about that too much.

Unless you are using the exact chamber and barrel that the manual had used, you probably won't get the exact same velocities. As for me, if I am 150 FPS under maximum, I will be happy with a safe and probably accurate load.

Here are the primers:

I did find some id marks on the 100primer cartons inside (didn't see these last night as I opened from the other side, and this is printed only on one side).

I do see "WCC" in the lot number...maybe Winchester after all?


This was the result. Not bad at all for using a 4x ACOG and a basic rest and prone from 100yds. I was shooting quickly for the sake of getting some velocity data and not worring as much about good technique for each trigger pull. I would shoot, record the velocity from the Chrony, shoulder the rifle, find my POI, and squeeze again. Maybe 30seconds between rounds.

Kinda wish I'd have been in less hurry and taken my time. Could have been close to a 1MOA group if I take out a few of the extremes that were probably all in my trigger pull (notice the diagnal patter from Top left to bottom right). The middle 6 are within 1", and 4 are touching. I think I'll load some more and try them again, this time with a little more focus on good technique. I may have just come across a very good load for my gun!

This was a 60gr V-Max loaded to mag length, and was out of a 16" Delton Chrome-lined 1:9 twist middy. Velocity was average of 2914FPS, and if I take out the two shots that were below 2900 (probably either a lighter charge or different case capacity, as these were mixed brass) the average jumps up to about 2925. Hodgdon's online reloading data shows max load of 24.0gr H335 should yield a velocity of 3075FPS. Maybe the difference is barrel length? Anyone know what Hodgdon and others use for their test data?


By comparison, some Federal American Eagle XM193 averaged 3067FPS from this same rifle, shot in a 10 round string just before this load.

 

[sloughfoot]

Those are indeed Winchester primer intended for use in WCC mil-spec ammo.

That is good shooting. Nothing at all to explain about that group.

The velocity is about what I would expect from a 16 inch barrel. The manufacturers usually use a 20 inch barrel for their 223 loads.

 

[jblomenberg16]

Those are indeed Winchester primer intended for use in WCC mil-spec ammo.

That is good shooting. Nothing at all to explain about that group.

The velocity is about what I would expect from a 16 inch barrel. The manufacturers usually use a 20 inch barrel for their 223 loads.

Thanks for the info on the primers, and for the comliment on my shooting! I may put a few of these through my Savage 10FP to see how they group through it. It is also a 1:9 barrel, and with the extra barrel length will probably pick up the velocity I'm losing from the 16" barrel.

 

[UncleMike]

Lyman 49th Edition, page 57 The variations in primer sizes or types can create substantial variations in ballistic uniformity. Rem 9 1/2 - 2509fps 52,800psi, Fed 210 Match -2508fps 53,100psi, CCI 200 - 2526fps 54,000psi, Win. WLR - 2539fps 54,700psi, CCI 34 - 2545fps 55,400psi TOTAL SPREAD 37fps 2,600psi. The above results were obtained by using the exact same 308 Win. load and only changing the primer. A change in primer will change the ballistics of a load, so we recommend that new reloaders use the exact components listed in our reloading data...

Yup!!
Back when I was a youngster, .357 Magnum cases that took large pistol primers would occasionally show up.
I reloaded them, but only after I consulted an OLD reloading manual that gave the appropriate powder reduction for .357 cases using the large pistol primers.

 

[sloughfoot]

Funny, how items that are not supposed to be available to mere mortals like us, like those WCC primers, show up every now and again. At one time, I procured 20,000 WSP primers in that familiar white box from an estate. Makes you wonder if an employee in East Alton has a little income coming in on "the side"?....

I guess they don't check lunch boxes at Winchester like they do at the Hershey chocolate factory.

 

[slackerisme]

IIRC during my research into loading, I remember reading that the real difference a primer can make is how quickly and thoroughly it burns the powder charge. Slower less powerful primers will result in a small delay before complete ignition. I remember it being minuscule, but unfortunately I do not remember the exact number. The .223 is a small rifle case, I would imagine the difference would be less pronounced. If you are working on a load, I would work it with the primers you have, chrono them to get a mean, and check again if you switch.

 

[redpitbull44]

I also want to point out that you may loose some velocity due to the fact that you are shooting an AR, and as stated, most likely a shorter barrel than the writers of the manual used.

 

[jblomenberg16]

I also want to point out that you may loose some velocity due to the fact that you are shooting an AR, and as stated, most likely a shorter barrel than the writers of the manual used.

In the end I think that is the most likely factor here, especially after I compared results to XM193. It was about 100FPS slower in my 16" gun than the milspec velocity from a 20" rifle, and would have been using a similar powder (I've read that H335 is a close approximation of the powder used in M193ball ammo).

 

[Big Naughty]

Lots of good info here. Thanks