Thread: Large vs small

Ok guys and girls. Got a question for you.If I loaded 2 bullets same powder and projectiles.
Only thing different would be one brass was large rifle primers the other small.
Would I see a difference in performance?
If I did 5 loads of each and shot them over the chronograph what would I see? Would I see different speeds? Has anyone done this?
Very curious too know. Cheers.

Yes
With all the usual caveats regarding reloading and variations in rifles. Noted difference are.....

SRP

Needs more powder to get same Vel

Can be harder to ignite (you can get hang fires)

Gives lower SD and ES

Gives more reloads per case (depending on your reloading regime)

Is it worth the change and subsequent load development? It does let you swap to what's available, but if a lot of people change then availability goes away as well.
Right now to change runs the chance of component substitution that could outweigh any benefits.

I run Rem 7 1/2 BR's for a hotter ignition flame, others will tell you they don't need to. Some people have to have their firing pin bushed.
Every situation is different.

Yes

Cheers for that. Was the answer I was hoping for. Something the think about now.

I'm running 308 SRP in Lapua and Peterson. Need to factor in the fact that the cost of SRP Lapua Palma is greater than LRP Lapua. And it seems that the Palma brass usually disappears off the shelves first although that may be due to maybe lower Palma quantities being imported versus the std case.

I run SRP for the improved SD and ES. Never had any hint of ignition problems - that would bugger up my nice SD and ES wouldn't it.
Some say you should run magnum primers to counteract the rumoured ignition problems and to bring the velocity back up closer to LRP performance.

And if you're into hot rodding (I'm not) the SRP brass is stronger in the base than the standard brass.

When I ran SRP in a 6.5 Creedmoor I had hang fires with feds and Belmont 760, swapped primers issue went away. Ball powder large charge and mild spark didn't mix well. Out of a string of 10 I found that I was having 1 to 3 hang fires.

Greetings,
Ball powders are harder to ignite and some older manuals recommended using Large Rifle Magnum primers for them.
GPM.

Use WW760 in my 6.5x55ai and only had one failure to ignite in 860 rounds fired. CCI BR2s. I believe it was a faulty primer.
Everyone said I MUST use a magnum primer. So I tried CCI Magnums. The supposed increase in velocity was minimal and my SD an ES and group sizes enlarged.
Continue to use CCI BR2s. YMMV


And interestingly the BR2s are nowhere near the top of the Primer Brisance Chart. @johnd your Rem 7 1/2s are right near the top so good choice.

SRPs work great with fast powers, ie 308, not so good with slower powders 6.5 CM

Also some rifles like RPR's don't hold hands well with SRP & top end loads, the firing pin is to big & primer too small = pierced primers

As mentioned previously you need to run more powder with the SRP to match the velocity of the LRP especially a magnum one, the beauty is you can

Interesting observations. My current experiments with cartridges that run both sizes have left me scratching my head. In 224 Valkyrie and 6.8SPC I have brass with both sizes. Using 224V Starline brass with smalls I can get ejector swipes and cratered primers in a Savage action at moderate pressures, and it's pretty similar in the 6.8SPC with LRP brass. But in a 6mmARC on a Savage action of the same era (so presumably similar tolerances), it will run tremendous pressures (like well above safe and sensible) without any pressure signs from either brass or primer.

I will say this , at the target you won't see any difference unless you are a .2 MOA shooter