The only primers i could lay hands on when i started reloading were federal magnum primers, my supplier now has large rifle primers in stock, should i switch and rework my loads or is there not enough difference to matter? BTW im using IMR 4831 if it makes any difference.

I have 2 270 and load for 3 more and I find that mag are to hot for some reason none of the mag primed loads give the consistence that standard rifle primers give even with the same powder charge ,oal ,case ect .

if what you have works well and your happy stay with it but i have better luck with standard primers .

I think I may try standards, Im shooting sub moa but everything you feed my 700 shoots decent groups. My best load right now with 110 v-maxs is 58 gr IMR 4831 shooting .6 inch 3 shot groups at 100

I have been able to get 140 grn accubonds to shoot in every 270 i have tried them in give them a spin if you have a chance they work great on deer and more.

My rifle loves accubonds, ive got some 140's just havent worked them up yet. Loaded some 110 accubonds for my girlfriend to shoot this week i think they should perform pretty well.

I asked JB that same question and he said normal primers are more than enough.

My 270 likes 140 grain accubonds as well.

the 110 and 100 were developed for the 6.8 spec so 270 velocities will really open them up i just got done testing a bunch of the 100 and 110 for ssa one function and fit cool job .

Nothing wrong with using mag primers under a case full of 4831 in a 270. I doubt you will detect any real difference if you elect to use reg primers. In this particular situation, I think primers are one of the less important variables.

I disagree I have had different brands of primers change identical loads by 3/4" in several different rifles. some like win ,cci ,rem ,magtec,ect and not necessarily all some rifles will take all but i have changed primers in a load and nothing else and went from 1 1/4" to sub moa more than once

But i do agree that if it shoots then go with it a 270 win is by all rights over bore an could have been advertised as a mag as well as the 25-06 and the rest of the wild cats up to 270win. The term just had not been used as a marketing niche yet ... I know it is not a mag just saying that it is over bore and their for could have been if that would have been the trend back then but the i guess it could have been an express.

Fr a long time I never gave the issue much thought until a buddy reported wide swings in velocity and less than great accuracy in his 270 and RL 22 with standard LR primers.I told him try Fed 215's.

So we set up the chronograph and found th 215's did far better in his rifle; velocities became more uniform, and groups also tightened.I have found the same using R22 in one of my 270's so use the Fed 215's there.I have also used Fed 215's with heavy charges of R25.

In a couple of others I use WW LR primers and H4831,which seems to work fine.

Reading back I discovered J O'C used CCI 250 mags in those famous H4831 loads of his.So, mag primers are not outta line at all with slow powders in the 270.

In all things .270 J O'C is not one to be debated. Its because of reading some of his articles when i was young that I bought my first rifle in .270 win. I was 16, it was a 700 ADL at the wally world and I slung feed for a whole summer to buy it and a Buckmasters 3x9

i will always try mag primers no matter what cartrige it is in if you are using slow burning powders or ball powders or some time very large charges ei. .45-70 up

I saw basically negligible difference in std vs mag primers in the testing I did with my 270. You have to actually shoot the gun and components in question to know for sure though.
JMHO
Tim