Will changing primers open up groups?

Dultimatpredator

Well-known member
I have been trying to find Remington 7 1/2 primers for almost three years with zero luck. My 223 LTR with shoot .3” groups all day long at 200 yards using 27.7 grains of benchmark, 40 grain NBTs, and the Remington 7 1/2’s. I haven’t tried another primer but I’m guessing changing to another brand primer with a different burn rate will cause my groups to open up?
 
Originally Posted By: DultimatpredatorMy 223 LTR with shoot .3” groups all day long at 200 yards using 27.7 grains of benchmark, 40 grain NBTs, and the Remington 7 1/2’s. I haven’t tried another primer but I’m guessing changing to another brand primer with a different burn rate will cause my groups to open up? If .3" at 200 yards with an LTR "all day long" is possible, then anything is possible. Changing primers might actually shrink your groups from .3" down to 1/4" at 200 yards all day long.
 
I understand this isn't your only gun that shots in the .3s @ 200 yards. Are you using the same primer with that one? Hope your able to find what you need.
 
I wouldn't care if a primer change doubled my groups to 0.6"@200yds. That's good enough for me 'cause I'm only gonna shoot a critters.
My best guess would be that the groups would be equal to or larger but I would go to a match primer. You might get a change in POI too but that is no big deal as long as you don't mix your ammo.
 
If you are only getting .3" groups @ 200 yds what have you got to lose? I would have tried some other brand long ago.
 
I'm by no means a great shot or even a great rifleman but I did happen to get lucky one day and won the Iowa State Championship back in 1984 in the benchrest heavy varmint division and never shot a 0.3" group on that particular day at 200 yards - neither did Larry Scharnhorst, Bob Dodd or Larry Kuse on that particular day in that particular State Championship Match.

You have one great shooting rifle there and are a subperb marksman to consistently shoot bugholes at 200 yards - my hat's off to you but I remain just a tad skeptical.
smile.gif


When you do run across some Rem 7-1/2's better purchase at least a sleeve, which is 5 bricks or 5,000 primers. I wish you well.

I'll add a couple pictures, for those who are skeptical.
smile.gif


https://i.imgur.com/w1xH7WX.jpg[/img]]imgur

Pb6Y5R6.jpg


 
Last edited:
To answer your question instead of doubting your group sizes.....anything you change, be it primers, brass, powder or charge weight is going to effect your group size. It could be better or it could be worse. The only way to really find out is to try and see what happens.
 
I changed brands of primers in my daughter's fast twist 22-250 because I ran out. It didn't affect the tune on it. Your results may vary...
 
Originally Posted By: pyscodogTo answer your question instead of doubting your group sizes.....anything you change, be it primers, brass, powder or charge weight is going to effect your group size. It could be better or it could be worse. The only way to really find out is to try and see what happens.


^^ this. only one way to find out.



ps: good luck finding ANY SR or SRM primers right now. no less by the whole brick
 
I think changing primers would have minimal effect. I’m talking casual hunting setups, not so much precision rifle competition. I’d rate it down the list compared to other factors, bullets, powder charge, COL & the biggies.

In this time of scarcity, one may have to substitute components, make do.
 
Originally Posted By: Plant.OneOriginally Posted By: pyscodogTo answer your question instead of doubting your group sizes.....anything you change, be it primers, brass, powder or charge weight is going to effect your group size. It could be better or it could be worse. The only way to really find out is to try and see what happens.


^^ this. only one way to find out.



ps: good luck finding ANY SR or SRM primers right now. no less by the whole brick

I agree with ALL of this ^^^^^^
 
Changing primers could open up the groups. The only way to find out, is to test it. I've done numerous tests with different primers and have never seen significant changes due to the primer but I know people that have and I've never been good enough to shoot 0.3" groups at 200 yards. I've shot 0.5" groups at 200 yards numerous times but I'm not good enough to do it consistantly. I've heard some people claim federal makes the best primers, other claim CCI bench-rest, Winchester or Remington. I'm going to be testing federal vs cci bench rest primers in my 223 to test what I buy next in bulk. I still have about 1000 Federal SR and at least a couple thousand CCI so I'm not in a rush to do my test. Maybe I should pick up some Remington 7 1/2 and Winchester. If I remember to, I'll post up my results. If you do some tests, let us know.

I've also been able to get great groups out of 40gr nosler ballistic tips from my 223's. Even if my gun were good enough to shoot 0.3" groups at 200 yards, I'm not good enough to pull it off. Even a 5 mph crosswind will open up my groups to 1" or more with a light bullet at 200 yards.

A few days ago I shot a 2" five shot group at 300 yards with my 223 and 40 gr Nosler BT when there was a 5-8 mph breeze. The center of the 5 shot group was about 1" from where I was aiming because I was off on my wind call. At 300 yards I was about 2 1/2" from my intended target. I was pleased with my shooting and feel that it is good enough for shooting coyotes at any reasonable range for a 223 pushing a 40 gr bullet. Prairie dogs at 400 yards is a different story. They keep me humble. I start missing those dogs more often than I hit them when I'm shooting 300 or 400 yards.
 
My .17 Hornet, .17 Remington, .204 Ruger, .221 Fireball, .223 and .223 AI have all shot their best groups with the CCI BR primer. Not my imagination. Why do my guns all shoot their best with this expensive and hard to find component? My guns that fire the large rifle are not nearly so fussy about what kind of cap they use but that is certainly not the case with my guns that use the small primer. Wish it was.
 
My load development works like this on a gun that has been bedded with the barrel freefloated, trigger tuned:

a. establish the distance to the lands, OAL

b. decide if you want to touch the lands, .005 off the lands, or .010 off the lands, then work up the best powder charge.

c. after you have the best powder charge, then play with seating depth to fine tune what the rifle likes, be open minded, the longer you do this, the more you will be humbled in your findings as there is no "etched in stone" way to do things.

d. Now when you have established the powder charge and seating depth, change primers with no other changes. Often you see groups cut in half while other times the groups are completely blown. Again, an open mind will continue to humble you as your most favorite primer or the primer you like or have the most of ends up being NOT the best for accuracy.

It has been said that you can tune an accuracy load for a particular primer, and I could not argue with this statement.

You just have to figure out a way that is best for you because there are so many variables this can drive you crazy.

The BIG issue here is seating depth...jeez...there is no grey area in that this is where major gains in accuracy are achieved. Use a Hornady or Davidson Ogive gauge, measuring off the tip of the bullet gives hit and miss results, especially between different lots of the same maker's bullets. The Hornady Ogive gauge works best with a case that has been fire formed in your chamber...very consistent results.

I got off subject from primer selection, but I have watched people struggle for years with load development.

In today's world of shortage of components, we struggle to have a variety of primers to choose from, and there is no end in sight to the shortage.
 
Originally Posted By: ackleyman
The BIG issue here is seating depth...jeez...there is no grey area in that, this is where major gains in accuracy are achieved. Use a Hornady or Davidson Ogive gauge, measuring off the tip of the bullet gives hit and miss results, especially between different lots of the same maker's bullets. The Hornady Ogive gauge works best with a case that has been fire formed in your chamber...very consistent results.

I do load development similar to ackleyman and agree with his post but his point about seating depth and more importantly the consistency of bullet seating as measured off the ogive can't be stressed enough.

People get real excited about how close they measure out the powder charge, which is great, but consistent bullet seating depth as it relates to the consistent distance of the ogive to the lands is an area many, many, many reloaders over look or flat don't pay attention to.

I measure every single loaded round from base to ogive and this is one of those areas where "close" is just not good enough. Once you get a load your gun likes, assuming nothing is out of whack somewhere, consistent seating depth will do more for producing accurate ammo than just about anything else.
 
Last edited:
Some folks even go to the extent of trying out a different lot of the primer brand/type that proved to be the best.

0.3 of an inch at 200 yards "all day" is something i would want to hold onto.

In the end though... Predator hunting is predator hunting and bench rest shooting is bench rest shooting.

I am satisfied with 2 inches at 200 yards "all day"

That just pile drives Coyotes.
 
Originally Posted By: RustydustMy .17 Hornet, .17 Remington, .204 Ruger, .221 Fireball, .223 and .223 AI have all shot their best groups with the CCI BR primer. Not my imagination. Why do my guns all shoot their best with this expensive and hard to find component? My guns that fire the large rifle are not nearly so fussy about what kind of cap they use but that is certainly not the case with my guns that use the small primer. Wish it was.

I understand this,,,, The Bench rest primers are more consistent and some manufacturers claim their more experienced personnel work on the BR line. I think that the BR line of primers are just a tiny bit hotter than the regular primers.
But whatever it is some loads work so much better with a match grade primer or bench rest primer.
 
The short answer is 'maybe'.

In my T-C Icon, 243W, a primer change from a CCI to a Rem 9 1/2, shrunk the groups by an inch, going from 1.5 to about .5 (at 100yds, 3 shot groups).

I've had other loads with that same rifle and different primers did not result in such a dramatic change.

However, .3 @200 yds. and I would suspect you will see a difference when a butterfly in the next county flaps it's wings.
 
Yes they definitely can. Like mentioned above, anything can.
I used the FGMM 215 magnums on my Norma and easily got sub MOA, then I decided to use the FGMM 210's and shrunk them (groups) to half of that, no variance in powder, bullet, seating depth etc.

I actually made a mistake reloading and didn't swap my 210's out from my 260 and primed 10 of my 338NM cases with them, so I shot a group, and it was significantly better.
 
Back
Top