I have been working up some loads for my Remington 700 VSSF in 220 Swift, and have found that H414 really likes to have a magnum primer. I get significantly lower standard deviations of velocity when using magnum primers as compared the CCI BR-2's, typically going from 40 to 70 down to 10 to 20 FPS. The group sizes are better as well. I was wondering if I might get a similar improvement using magnum primers with IMR4046, the other powder I am working up. I would reduce the load and work it back up again, of course. I did see one manual that indicated a magnum primer with H414, but not for 4064. Any one out there have this experience?

The ball powder like H414 is supposed to be harder to ignite, so most use a magnum primer. With 4064, use a standard one. By the way, I've always had good performance with H414 in the .220.

I've been using H414 in many of my calibers including 338 Win Mag, '06, 7x57 etc. I use standard primers (Fed210M's) with no problems and good groups.

Bob257

Obviously the load you are working with likes the "magnum" primers better than the CCI's (you don't mention the brand of the "magnums").

That may or may not be true with another load or another powder.

I use "standard" primers (RWS) with a very slow ball powder in large capacity cases (WC 872), and experience excellent results.

My point is, there is probably less difference in "standard" and "magnum" primers than there is in brand-to-brand variations. Use whatever works best for the individual load.

I usually start with a mag primer on ball powders especially if they run 40gr or more , extruded usually around 60gr. Just a guide line for me certainly not a hard fast rule. I've had excellent results with H414 in .22.250's , 7.08's and .06's all with mag primers. Look in Speers manual you'll find mag primers on all (I think) ball powder loads. As Stonecreek pointed out all that matters is what works. A guy does however want to be very careful working up a solid load and arbitrarily changing primers , unless he's looking for some real excitement.---Shoot Safe---montdoug

By the way, I don't get too carried away with standard deviation, as I've had some pet loads over the years that varied 60-70 fps and shot great. Until I got my first chrono. 25 years ago, I never knew the difference. Most really good loads don't seem to change point of impact or group size much as powder charges go up or down quite a bit.

I agree with Stonecreek. I recently worked up a 30-06 load with W760. I got not only less deviation and better groups with a standard CCI primer than I did with a Winchester magnum primer, but I also got as much as 100 fs more velocity with the CCI as well. Perhaps if I tried a CCI magnum primer??

Thanks for all the comments. I was comparing using CCI Magnum primers to CCI BR2 benchrest primers. I have subsequently found out that it did not make much difference with the H414, and none at all with the 4064. The dominant factor with all the test loads was case volume. The loads with the largest filled volume had the lowest deviations. This included effects of bullet seating depth. I'll stay with the CCI BR2's for now.