.243 Win. with Small Rifle Primer Brass - Anyone Tried This?

[South Pender]

I posed this question on another thread that wasn't getting much attention. So let me start a new thread with the question:

Has anyone with a .243 Win. tried the Peterson SRP (small rifle primer) brass? I'm assuming this was designed for better accuracy in the .243.

 

[guntech]

I have not and I don't know anyone who has. I know with the 308 case and small primers there was some success with a shortened case... about 1.5 inches if I remember correctly. I believe the theory is a smaller narrow flame down the middle of the powder may ignite the powder column more evenly resulting in more accuracy... I don't know, maybe I am just blowing smoke out my ass... now I am going to google it a bit and see what pops up.

google = Many competitive shooters prefer Small Rifle Primer pockets (SRP) because they experience longer primer pocket life due to the increased material in the head of the case. There is also a belief that Small Rifle Primers produce a more consistent ignition.

 

[JJ-65]

Ok with cci 450’s, single base stick powder and warm weather. Everything else is a crap shoot.

 

[DANS40X]

I've run Remington URBR in 22-250,243,6.5-08,260Rem,7mm-08,7.62x51 & 308 Win for decades.

Remington URBR is small primer pocket 308 brass manufactured to make 22BR,6mmBR & 7mmBR prior to Remington manufacturing ammo.


Depending on powder & temperature(s) the flash hole diameter is critical, as those who drank the Lapua 308Palma brass(SRP) KoolAid found out eventually!!

(.062" diameter is TOO small)

 

[Suther]

I've run Remington URBR in 22-250,243,6.5-08,260Rem,7mm-08,7.62x51 & 308 Win for decades.

Remington URBR is small primer pocket 308 brass manufactured to make 22BR,6mmBR & 7mmBR prior to Remington manufacturing ammo.


Depending on powder & temperature(s) the flash hole diameter is critical, as those who drank the Lapua 308Palma brass(SRP) KoolAid found out eventually!!

(.062" diameter is TOO small)

Is the flash hole on a case that accepts SRP smaller than a case that accepts LRP? (speaking in general terms of course)

 

[Potashminer]

Suther - As per another recent CGN thread - I went looking on Internet - I think I found all combinations - cases being sold with Large Rifle Primer with both large and small flash hole; also cases being sold with Small Rifle Primer with both large and small primer hole - for otherwise identical chamberings. Was not found for all cartridges, but found some of each combination. "Small" flash hole was typically given as 0.060" (1.5 mm) or smaller - "Large" or "Normal" flash hole typically given as 0.079" (2 mm) or larger. I also found some posts in some chat rooms about people buying "small" flash hole brass and then drilling out to be like 0.070" or something else - but smaller than "normal" size.

Is no doubt some people own rifles with barrels so precise and hand loading process so dialed in that they could show difference in group size by varying the flash hole diameter. I do not own anything like that, so is not something that I worry too much about. I certainly have never even "uniformed" flash holes to know they are all the same - maybe something that I should start doing - is long winters we have in Manitoba - need something to keep busy at.

 

[South Pender]

I have not and I don't know anyone who has. I know with the 308 case and small primers there was some success with a shortened case... about 1.5 inches if I remember correctly. I believe the theory is a smaller narrow flame down the middle of the powder may ignite the powder column more evenly resulting in more accuracy... I don't know, maybe I am just blowing smoke out my ass... now I am going to google it a bit and see what pops up.

google = Many competitive shooters prefer Small Rifle Primer pockets (SRP) because they experience longer primer pocket life due to the increased material in the head of the case. There is also a belief that Small Rifle Primers produce a more consistent ignition.

Yes, I saw that on the Peterson website. I guess I'm looking for some real evidence, rather than "there is also a belief" regarding more consistent ignition and, perhaps, better accuracy. One thing in that Peterson description that gave me pause is the possibility of needing a "bushed firing pin" with this brass because of the increased chance of a pierced primer. I'm having a little trouble understanding this. I've heard of bushing the firing pin hole in the bolt face--maybe that is what is meant--but I still don't see why doing this would reduce the chances of pierced primers. Guntech, can you explain how this would help?

 

[South Pender]

Suther - As per another recent CGN thread - I went looking on Internet - I think I found all combinations - cases being sold with Large Rifle Primer with both large and small flash hole; also cases being sold with Small Rifle Primer with both large and small primer hole - for otherwise identical chamberings. Was not found for all cartridges, but found some of each combination. "Small" flash hole was typically given as 0.060" (1.5 mm) or smaller - "Large" or "Normal" flash hole typically given as 0.079" (2 mm) or larger. I also found some posts in some chat rooms about people buying "small" flash hole brass and then drilling out to be like 0.070" or something else - but smaller than "normal" size.

Is that right? So there are large primer pocket cases available with the smaller flashhole and small primer pocket cases available with the large flashhole? I didn't know that.

 

[Suther]

Suther - As per another recent CGN thread - I went looking on Internet - I think I found all combinations - cases being sold with Large Rifle Primer with both large and small flash hole; also cases being sold with Small Rifle Primer with both large and small primer hole - for otherwise identical chamberings. Was not found for all cartridges, but found some of each combination. "Small" flash hole was typically given as 0.060" (1.5 mm) or smaller - "Large" or "Normal" flash hole typically given as 0.079" (2 mm) or larger. I also found some posts in some chat rooms about people buying "small" flash hole brass and then drilling out to be like 0.070" or something else - but smaller than "normal" size.

Is no doubt some people own rifles with barrels so precise and hand loading process so dialed in that they could show difference in group size by varying the flash hole diameter. I do not own anything like that, so is not something that I worry too much about. I certainly have never even "uniformed" flash holes to know they are all the same - maybe something that I should start doing - is long winters we have in Manitoba - need something to keep busy at.

So what you're telling me is its a crapshoot. Good to know, yet not surprised. lol

 

[Potashminer]

"crap shoot" - not really sure what you are referring to - should not really be surprised at what you bought - I would think it would clearly say so on the package? And for sure, the various rifles here are not high end bench rest things, nor am I a high end shooter - so will take more than what I can do or what I own to show that all makes a difference. I think some modern "target" type cartridges are ONLY made with the small flash holes, and perhaps some elderly designs like 30-06 might ONLY be made with normal size flash holes.

For sure would be a "shocker" to discover that your trusty old RCBS de-capping pin in your elderly sizing die, will not fit into a new-fangled small flash hole brass - even though the primer pocket is still same size.

 

[South Pender]

Perhaps the fact that most high-precision shooters seem to use small primer pocket (and small flash hole) brass is evidence of its superiority, but it would be nice to see some careful empirical results confirming this.

 

[Suther]

"crap shoot" - not really sure what you are referring to - should not really be surprised at what you bought - I would think it would clearly say so on the package? And for sure, the various rifles here are not high end bench rest things, nor am I a high end shooter - so will take more than what I can do or what I own to show that all makes a difference. I think some modern "target" type cartridges are ONLY made with the small flash holes, and perhaps some elderly designs like 30-06 might ONLY be made with normal size flash holes.

For sure would be a "shocker" to discover that your trusty old RCBS de-capping pin in your elderly sizing die, will not fit into a new-fangled small flash hole brass - even though the primer pocket is still same size.

By crap shoot I mean there is no consistency or correlation to it. (it basically means something with an unpredictable outcome)

Perhaps the fact that most high-precision shooters seem to use small primer pocket (and small flash hole) brass is evidence of its superiority, but it would be nice to see some careful empirical results confirming this.

But then that begs the question WHY do they use it? Do they use it because it lasts longer, as Guntech mentions with regards to the primer pockets, or is it more accurate, or perhaps both? Maybe there is a different factor we are not considering?...

 

[Mystic Precision]

For my 308Win FTR setup, I ran Lapua SR and LR brass.. Varget was the powder.

I used SR for the summer and LR in the cooler months.

I did not modify the FH that came with the brass. Both types shot very well.

Jerry

 

[jamesharrison]

There was a series of articles about this in both Precision Shooting and The Accurate Rifle magazines back in the day.

The series revolved around the use of necked-down & blown-out 7.62x39 (LRP) brass, versus the at-the-time un-obtanium .220 Russian / 6PPC (SRP) small flash-hole brass.

 

[guntech]

Yes, I saw that on the Peterson website. I guess I'm looking for some real evidence, rather than "there is also a belief" regarding more consistent ignition and, perhaps, better accuracy. One thing in that Peterson description that gave me pause is the possibility of needing a "bushed firing pin" with this brass because of the increased chance of a pierced primer. I'm having a little trouble understanding this. I've heard of bushing the firing pin hole in the bolt face--maybe that is what is meant--but I still don't see why doing this would reduce the chances of pierced primers. Guntech, can you explain how this would help?

I know it is common to talk about pierced primers but primers don't pierce, they blow out or "blank". About only way one will pierce is if the firing pin tip is so pointed it cuts into the primer. When a firing pin is bushed it is so there is very little clearance between the firing pin hole and the firing pin tip... this gives the most support to the bolt face and the primer. Often when the bushing is done the firing pin tip may be reduced to about 60 thou. That will accept higher pressures before primer failure if the firing pin is strong (as 700 springs are). Firing pin protrusion between 40 and 50 thou works well.

 

[South Pender]

I know it is common to talk about pierced primers but primers don't pierce, they blow out or "blank". About only way one will pierce is if the firing pin tip is so pointed it cuts into the primer. When a firing pin is bushed it is so there is very little clearance between the firing pin hole and the firing pin tip... this gives the most support to the bolt face and the primer. Often when the bushing is done the firing pin tip may be reduced to about 60 thou. That will accept higher pressures before primer failure if the firing pin is strong (as 700 springs are). Firing pin protrusion between 40 and 50 thou works well.

Great, guntech. That makes a lot of sense. I'm wondering whether the back pressure is greater when blasting the flame through a smaller flashhole (like the .060" small primer size) than a larger flashhole (.080"). If so, this might help explain the need for bushing the firing pin hole.

 

[guntech]

Great, guntech. That makes a lot of sense. I'm wondering whether the back pressure is greater when blasting the flame through a smaller flashhole (like the .060" small primer size) than a larger flashhole (.080"). If so, this might help explain the need for bushing the firing pin hole.

I believe the bigger flash hole allows more pressure onto the primer from the case on firing...

 

[Potashminer]

Is that right? So there are large primer pocket cases available with the smaller flashhole and small primer pocket cases available with the large flashhole? I didn't know that.

I do not have examples of the first combo - Large Rifle primers and small flash holes - but is several references on this thread to others that have those. But Small Rifle Primer and large flash hole - did not need Internet - is hundreds, maybe thousands of .223 Rem aka 5.56 NATO that are here - some commercial and some mil-surp - exactly like that. That I know of, I do not think any Boxer primed brass here has the small flash holes (between 20 and 25 different cartridges).

 

[Suther]

I do not have examples of the first combo - Large Rifle primers and small flash holes - but is several references on this thread to others that have those. But Small Rifle Primer and large flash hole - did not need Internet - is hundreds, maybe thousands of .223 Rem aka 5.56 NATO that are here - some commercial and some mil-surp - exactly like that. That I know of, I do not think any Boxer primed brass here has the small flash holes (between 20 and 25 different cartridges).

Have you heard of small rifle primer, large flash hole on a case that normally takes a LRP?

I'm just thinking that flash hole variation on 223/556 when its ALL small rifle primer might be muddying the waters? (that is to say I'm not sure 223/556 brass differences are going to help determine if there is a correlation between flash hole size and primer size for 243win, 308Palma, etc)

 

[South Pender]

I do not have examples of the first combo - Large Rifle primers and small flash holes - but is several references on this thread to others that have those. But Small Rifle Primer and large flash hole - did not need Internet - is hundreds, maybe thousands of .223 Rem aka 5.56 NATO that are here - some commercial and some mil-surp - exactly like that. That I know of, I do not think any Boxer primed brass here has the small flash holes (between 20 and 25 different cartridges).

Yes, of course, you're right. My Lapua .222 Rem. brass has the small rifle primer, but large .080" flashhole, and, as you say, probably all .223 Rem. brass is the same. So there appear to be two variables working here--(1) primer size and (2) flashhole diameter—and it might be necessary to consider each independently. The Peterson .243 Win. SRP brass has the small (.060”) flashhole, and I suspect the same is true of the SRP Lapua brass.