Is there any downside to working up loads with Win Mag primers in a 270 Winchester. I have 1200 that I'd like to use up. No longer have a magnum rifle.

They work fine, but sometimes you have to reduce your load a bit.
They work best with ball powders.

I've used magnum primers for the .30-06 case....they work fine. Further it hasn't been my experience that I needed to reduce the powder charge.....but don't assume that's true across the board...back off and work back.

While it's often assumed that magnum primers work best on ball powders....I'm not disputing this.....they also work fine on avery other powder under the sun.

If you have them.....use them.

It's so nice that things have loosened up, component-wise, so that we can even entertain such ideas! (They work just fine with H4831, RL26, or RL22 so commonly used in the 270.)

Funny thing is sometimes mag primers will give better accuracy in the 270 than standard. You've just got to try to know.

Regardless, as others have said, you may have to back off a bit charge-wise, but they're certainly just fine with any powder, stick or ball, that works in the 270.

My 2 cents, No downside, irregardless of powder choice. This caliber has proven to be one of the easiest to get along with, in that it seems difficult to find reasonable combinations that don't work.

It begs the question, Why? in my opinion, if you use less than 75gr of powder Mag primers are not needed.

That's not my experience. Many times magnum primers have resulted in considerably better accuracy when using powder charges under 75 grains, and sometimes with far smaller charges. Often that occurs with spherical powders, but sometimes not.

One good example occurred the first time I used Ramshot Big Game over 15 years ago. The rifle was a .220 Swift and the powder charge around 40 grains. Velocity was great but 5-shot groups at 100 yards were well over an inch. Switching to a magnum primer cut group size in half.

In magnum-sized cases a good example is my custom .338 Winchester Magnum. With 200-grain Ballistic Silvertips, 67 grains of Reloder 15 and magnum primers, average accuracy for 3-shot groups is around .6 inch. With standard primers accuracy is very mediocre.

Could provide a bunch of other examples.

Maybe if you use ball powders like H414 in cold weather, otherwise, mag primers not needed.

My go to 270 load with 130gr bullets is WLRM primers over H4831. I found early on that I got better accuracy with WLRM vs WLR.

I also have 3 pounds of Reloder 26 that load development will start with magnum primers in my 270.

The only time my groups did not improve when going to a smaller primer was with the 257 Weatherby (71.3gr MRP). In my 338 and 375 however, the accuracy improved dramatically when I went to 210 Primers in the 338 (73gr RL-19 for a 210 TTSX and 71.3 for the 250gr Nosler Partition or TSX) and in the 375, with both 300 and 270 grain loadings. this was not my original thought. A fiend of mine recommended this and he got it from a Federal ballistics guy years ago.

I have one magnum rifle and use mag primers in it. I purchased some primed 25-06 on a forum that came with mag primers already in place. So, I worked up a load and used them up. Switched to BR2's and never looked back.
I've never had to reduce or change a powder charge because of the mag primers making the round too hot. They will change how the round groups though. It's just one of the things you can change that will have an effect on your loads.

If you want to use them up, use them up. You might just end up buying more of them from the improved results.

Sometimes they act better than std. primers.

I've used magnum primers a lot in non mag cartridges. I see no downside whatsoever. In fact in my 30/06 180 grain Ramshot Hunter load a mag primer cut groups in half and ES numbers went from a spread of about 70 fps down to 6 fps. For the most part however accuracy has been very similar in switching between mag or non mag primers. I've noted about 25 to 30 fps gain in velocity useing a mag primer in 06 size case. The velocity gain is free considering a mag primer cost the same as a non mag primer.



Trystan

I think they give more consistent ignition, I use Federal magnum match primers a lot in 25 06 and larger cartridges a good bit. I try large rifle first.

Hanco,

I don't know if this is a myth or not but I've often heard what you mentioned is especially true when hunting in sub freezing temps. I haven't been able to substantiate the claim for myself however I do take note of it as its been mentioned by some I consider to be knowledgeable.


Trystan

I work up loads for any powder slower than H4831 and cases 06 or larger with magnum primers first. I can then switch to a standard primer with minimal load work up as the mag primer usually though not always will have a higher pressure at least in theory.

No rhyme or reason as to which will be more accurate. I do see more consistent velocities with the mag primers with some load combo's.

I use CCI 250 and RE 19 in my 3006 and shoots fantastic.

My testing of mag primers in 270 gave no positive gains over Fed Match or WLR.
But that was me, my gun and the powders and bullets I use.
Now I am old enough that if it shoots good, I don't care to chase a couple fps.
Tim

Thanks men. I've got what I needed and I appreciate your replies.

Rug

I use mag primers with in my 270loads with H4831. Groups better with the mag primers.

Whelen Nut

It's been a while since I've heard from you. Hope things are going well. Thanks for the above helpful information.

Jim

I use magnum primers in my .270's with good luck and cannot see how better ignition wouldn't be a a good idea,especially in cold weather shooting. I had read this a long while ago -it is not my idea,but it works for me with all 270 win powders.

I run magnum primers on only one load my cold weather elk. Use the CCI 250 to light up 52.0 grains of IMR 4831 pushing the 160 Nosler partition. Very accurate, very powerful 270 load.


41

I run CCI 250 primers with 60gr of 7828 and 130gr bullets(Hot Cor, Grand Slam or Partition), seems to work better than anything else in my 270.