If your 5.56 rounds are a little Hot, with just a Small Rifle Primer, what happens if you use a Magnum Small Rifle Primer ?
I figure it lights the powder a little more forcefully, and so generates that much more pressure, from faster burning.
Using 27.5 grains of Ramshot Magnum with a 75 grain Speer Gold Dot or 77 grain Sierra Matchking.
27.5 grains = 1.782 Grams.
I find that Magnum, Winchester 760/ Hodgdon 414, and Accurate 2700 are similar in burn speed.
I tried using that amount of BLC2 (mid range powder), with the 75 & 77 grain bullets. It blew out the primer or showed other signs of mild over pressure.
If barrel length affects the answer to the question, it’s using a 24 inch barrel.
I’ve been using CCI 400 or No. 41 mil spec small rifle primers.
Are the Magnum Small Rifle primers more for 6.5 Grendel / 450 Bushmaster, the bigger loaded bullets that have small rifle primer pockets ?
I don’t have any experience with magnum rifle primes, but I have used magnum pistol in place of regular primers with no noticable effects. I think your loads would have to be on the ragged edge of max pressure before you would see any negative issues.
I had read somewhere that mag primers burn a little hotter which can cause the powder to burn a little faster which of course builds pressure faster. Not sure how much of that is science or conjecture though. I also think your load would have to be on the hairy edge for it to make a difference.
I have used magnum primers in place of SR a few times and made no adjustment to “normal” loads and noticed nothing different at all. I have buddy who uses SRM exclusively and swears by them in all his SR loading. He has many more years experience than I. Discussing a cycling issue I was having with him he suggested the magnum primers ignite quicker, but do not change the burn rate of the powder - which the speed of the powder and the buildup of pressure wave has to be timed to your particular rifle. Basically - different rifles (24" w/rifle length gas tube vs a 16" w/carbine length gas tube) demand different pressure waves for perfect timing to cycle the gun. Since there are so many gun variations out there - most guns are basically set to over gas so they will function with nearly any round. ALso - most factory loads are loaded to higher pressures so they will fire in all guns. I’ve seen guys much more experience tune specific loads to specific guns and have them tuned down so far, there is virtually no recoil. I’m not that critical or detail oriented, plus I have several guns and want them all to function with whatever round I have (in a SHTF scenario)
LBL…I went back an looked at your post and saw you were using Ramshot Magnum powder with 75/77 grain bullets. Has this load worked for you?
I don’t know this powder but looked it up and it is one of the slowest burning powders out there and Ramshot (Western) doesn’t show any load data with this powder in .223 cartridges at all for any bullet weight. All the other powders you listed are on the middle to slower end but right together in terms of burn rate, with the Magnum being further down at the very bottom of the burn rate chart. All these powders seem more suited to 30-06 or other medium sized cartridges but not .223 bullets at any weight. I could not find any published load data for any of those powders for .223. Also 27.5 gr sounds like a lot for any .223 load. I don’t know these powders and I have only used 6 or 7 different powders for 223 in my loading experience, but 27.5 sounds high to me.
Not criticizing - just curious. I have only been loading a few years and always interested in others’ input.
I tend to like Bigger Grains. The Ramshot grains are complete sphere shape, like tiny ball bearings.
So partially, I just prefer doing manual loading with the Ramshot product, than with the 2 or 3 others.
Mainly just trying to get as many foot pounds as possible with the 75 & 77 grain 5.56’s.
If someone told me I would do better with 1.6 grams of Benchmark than with 1.75 grams of the slower burning powder, I would consider the Benchmark. Which I use for 308.
The last year, I’ve been shooting mostly 308.
Then 3 months ago ended up working full time on wildfire prevention stuff.