Pros and Cons 6.5 Small Primer vs. Large Primer

[Bmoore0062]

So looking to swap barrels of my 308 RPR over to 6.5 Creedmoor. New to the caliber and been reading up on small primer vs. large primer.

Was wondering if anyone has expirence with both. What are the pros and cons? I found the article below handy.

Just wondering if the benefits are worth the hassle? Will I need to bush the firing pin and Will I be restricted only to using that bolt in the future with small rifle primer?

Sorry if this is the wrong forum but I do believe this is more of a reloading question.

https://rifleshooter.com/2018/05/do...dmoor-small-v-large-primer-brass-comparisons/

 

[MarinePMI]

A bushed bolt has no restriction for use with just SRP cases.

Personally, I wouldn't bother. The SRP cases tend to run slightly slower velocities, and while the cases last longer (in theory) I've got Hornady cases on their 10th reloading so I have to ask, how long do we need the cases to last? If you don't anneal this is a moot point as well, since the case necks will crack/split long before the primer pockets let go.

If it ain't broke...

 

[IDbound]

I noticed that my accuracy improved from leaving Hornady brass and moving to SRP Lapua brass. Just my 2 cents.

 

[JimLee]

So looking to swap barrels of my 308 RPR over to 6.5 Creedmoor. New to the caliber and been reading up on small primer vs. large primer.

Was wondering if anyone has expirence with both. What are the pros and cons? I found the article below handy.

Just wondering if the benefits are worth the hassle? Will I need to bush the firing pin and Will I be restricted only to using that bolt in the future with small rifle primer?

Sorry if this is the wrong forum but I do believe this is more of a reloading question.

https://rifleshooter.com/2018/05/do...dmoor-small-v-large-primer-brass-comparisons/

My 6.5 RPR shoots SRP just fine, in fact thats all i've shot since the day it came out of the box. Theoretically we have the same bolt so you should be fine. As stated above the only real advantage of SRP that I have seen proven is brass life, the primer pockets tend to go first on LRP.

 

[HoustonB77]

Unless you have a small firing pin I would stick with LRP. I had issues with SRP and a standard pin.

 

[whatsupdoc]

Dont mean squat, I use both in 6.5 creed.
I was using lapua brass only to acquire a bunch of free hornady brass.
They both shoot between .5 and .75 moa for me so dont sweat it.
Go out and have fun.

 

[mustang-cars]

My RPR was a no-go with SRP Alpha brass. Very mild loads with CCI 450 primers would cause the primer to flow into the firing pin hole pretty substantially. I'm sure with the manufacturing tolerances every RPR is different.

 

[JimLee]

My RPR was a no-go with SRP Alpha brass. Very mild loads with CCI 450 primers would cause the primer to flow into the firing pin hole pretty substantially. I'm sure with the manufacturing tolerances every RPR is different.

Primer flow is usually more indicative of a firing pin being too small for the bolt. With a firing pin that is too large for the primer you usually get inconsistent or no ignition of the primer. Putting a undersized firing pin in a bolt without a bushing is what usually causes this. You should send your bolt back to Ruger if these are all factory parts.

 

[Soulezoo]

I saw a similar article/test to the posted link. However, that test used Lapua brass vs Hornady brass. So not like the linked article that managed to get starline for both and thus more apples to apples.
I couldn't find the article I was referring to, however, I do recall that SD's greatly favored the LRP, like this linked article. I don't recall accuracy or velocity differences.
In the end, the differences overall were (like shown here) very minor as to be a non-factor in my mind.

The accuracy differential may very well be unnoticed seating depth differences too.

 

[waveslayer]

I thought I read that the Large rifle primers seemed to perform better in cold weather, I could be lying

 

[JimLee]

I thought I read that the Large rifle primers seemed to perform better in cold weather, I could be lying

I guess that's a possibly, hadn't read that but it's worth investigating, most are using magnum primers in the SRP brass so that may offset the difference a bit.

 

[emann1022]

I have an AIAT with the large firing pin and shoot small primer brass in 308, 6.5 Creedmoor and 6.5x47L. I haven't pierced any primers or had any noticable issues.

 

[mustang-cars]

Primer flow is usually more indicative of a firing pin being too small for the bolt. With a firing pin that is too large for the primer you usually get inconsistent or no ignition of the primer. Putting a undersized firing pin in a bolt without a bushing is what usually causes this. You should send your bolt back to Ruger if these are all factory parts.

Yes bolt and parts are all factory. Action has about 5,000 rounds on it though. I have a firing pin from anarchy outdoors. I don’t want to deal with sending it back to Ruger. I’d have to put it back to factory condition and I’m not into that. Just used the LRP Alpha brass I have.

 

[mustang-cars]

I thought I read that the Large rifle primers seemed to perform better in cold weather, I could be lying

I just shot a match with my Defiance with SRP Alpha brass and CCI 450’s. It was 20 degrees out everything worked great!

 

[Ripdog28]

Primer flow is usually more indicative of a firing pin being too small for the bolt. With a firing pin that is too large for the primer you usually get inconsistent or no ignition of the primer. Putting a undersized firing pin in a bolt without a bushing is what usually causes this. You should send your bolt back to Ruger if these are all factory parts.

Not completely true. Large firing pins on a small primer tend to rip the primer on the outer edge of the FP indentation. Since the primer is smaller, there is less flat area to flex, the indentation from a Large FP gets into the harder surface caused from the curve of the primer causing a rip. Large primers having more flat surface have more area unaffected by the curve and stretch easier. Also cheap primers often rip. seen this on Fiocchi Pistol primers. Over charged/ over pressured cases can bulge the primer causing it to push back and puncture. Several reasons can cause primer flow.

OP, each individual rifle is different, some Large FP work just fine, some need a small FP.

 

[spife7980]

I thought I read that the Large rifle primers seemed to perform better in cold weather, I could be lying

You’re right, Tubb chooses large primer for that reason, to reduce hang fires from insufficient ignition. He is coming out with some small primer xc cases but he said that’s just because of demand, he’s finally giving into it at our own peril.

 

[JimLee]

Not completely true. Large firing pins on a small primer tend to rip the primer on the outer edge of the FP indentation. Since the primer is smaller, there is less flat area to flex, the indentation from a Large FP gets into the harder surface caused from the curve of the primer causing a rip. Large primers having more flat surface have more area unaffected by the curve and stretch easier. Also cheap primers often rip. seen this on Fiocchi Pistol primers. Over charged/ over pressured cases can bulge the primer causing it to push back and puncture. Several reasons can cause primer flow.

OP, each individual rifle is different, some Large FP work just fine, some need a small FP.

I agree, but he said he was getting primer flow on light loads and nothing about torn or pierced primers. He is also running an aftermarket firing pin. The problem he is describing is pretty common when people swap in small firing pins without a bushing.

 

[Sportin Wood]

Whatever you have a ton of primers in. I moved from a 260 barrel on my AIAX to a 6 Creedmoor. I also have a 6br and 6brx barrel in the works. With the small primer pocket of the br brass, I chose to go with Alpha SRP 6 Creed brass. In this case I bought a few thousand cci 450's and bushed my AIAX bolt.

 

[Ripdog28]

I agree, but he said he was getting primer flow on light loads and nothing about torn or pierced primers. He is also running an aftermarket firing pin. The problem he is describing is pretty common when people swap in small firing pins without a bushing.

We both know people frequently say one thing but word it incorrectly. The poster with the issue should post pictures so it can be diagnosed properly. Gassed flowing back, flat primers, createred primers, etc are all frequently worded as primer flow.

 

[Bmoore0062]

I saw a similar article/test to the posted link. However, that test used Lapua brass vs Hornady brass. So not like the linked article that managed to get starline for both and thus more apples to apples.
I couldn't find the article I was referring to, however, I do recall that SD's greatly favored the LRP, like this linked article. I don't recall accuracy or velocity differences.
In the end, the differences overall were (like shown here) very minor as to be a non-factor in my mind.

The accuracy differential may very well be unnoticed seating depth differences too.

Thanks, like serveral other people said “if it not broke” Seems like the benefits may be marginally noticeable. So I probably will not bother with the SRP, just load and shoot. I’m sure I will benefit from more trigger time than anyways.