johngibbs222
Well-Known Member
- Joined
- Jun 15, 2012
- Messages
- 212
My 0.02$ worth is to get to know your components.
SRPs advantages are several.
Nowadays, in many areas, availability is a major issue ie in my neck of the woods srp are more available than lrp, are cheaper so I bought a rake of cases with sr p cavities.
Single base powders tend to fill the case more than similar performance loads of double base powders, the closer you get to 100% fill the better from an accuracy perspective. (I understand it's one of the reasons that Varget does so well in 308 sized cases)
Single base powders, in general, are more consistent and ignite easier than double base powders especially in cold weather so srp are not disadvantaged. There is a corollary to this statement and that is double based powders are more difficult to ignite thoroughly than single base powders so don't use double base powders with srp in medium sized cases if low sds and consistent velocities are what you are after.
There are other differences but they tend to be open for debate whereas it's hard to argue with the statements I've gathered together and stated above.
I bought Peterson 308 cases with srp because I had many more srps than lrps, I use single based Vhitavuouri powders and do not load to DNE levels. In honesty the loads I use do not shade my 30/30 by more than around a 300 fps difference in muzzle velocity with 150 grn jktd, with the 30/30 loaded with LRP and H-LVR or CFE 223 but the accuracy difference is marked ( as you'd expect).
SRP cases are not pixie dust but they do work well with full cases of single based powders, TBH this old man can't brag about the improvement in accuracy as I'm not a particularly gifted rifleman.
So in answer to the question from my mates I always say I got nearly 6000 srps but only 2000 lrps that's why and it seems to satisfy them especially as they get to see how I shoot on the range.
FWIW economics didn't enter into my equation, for the same price per hundred for peterson unloaded brass I could have bought 140 7.62x51 (308) GGG palma 155 grn match ammo.
With all that in mind, I now return to the OP's original question, almost. I compared peterson srp loaded with 43 grains of N150 and Speer 168 match BTHP using Magtech srp v Federal brass with the same load of N150, same bullet and Magtech LRPs.
Going from a 80 year old memory, my Magnetospeed sporter chrono said the federal loads were between 25 and 50 fps quicker than the Peterson, most of the variance was from the Federal loads, the Peterson ones were remarkably consistent. Ambient temperature was around mid to high 70s and the range is at sea level almost.
As I indicated at 100 yards not a great deal of difference using my 20" barreled Browning BLR 81, I wouldn't like to call which was better. No pressure signs that I could see.
When I reloaded them in my LEE hand press I could FL resize them both reasonably easily. FWIW the Federal have over 10 reloads each the peterson brass was on its first outing. After each load the full cartridges drop into and out of my hornady headspace gauge with a little headspace showing.
For interests sake, before loading I fitted a bullet in each of the cases to the stated COAL and measured the potential capacity of both cases, IIRC the federal was about 1 grain wt of water smaller at 47.2 grains of water, a figure I recorded to use on my software to predict pressure.
Here's a vid of that measuring procedure .
Once again, IIRC, pressure prediction for both loads was in the low 50K range which suits me just fine, the velocity predictions again using my erratic memory were both around 2500 +/- and the actuals were about 50 ish higher.
I apologise for being a little vague on this issue but I no longer use those bullets, I've settled on 130 grn barnes tsx and 178 grain cast gas checked. They are quite a bit faster and quite a bit slower respectively.
SRPs advantages are several.
Nowadays, in many areas, availability is a major issue ie in my neck of the woods srp are more available than lrp, are cheaper so I bought a rake of cases with sr p cavities.
Single base powders tend to fill the case more than similar performance loads of double base powders, the closer you get to 100% fill the better from an accuracy perspective. (I understand it's one of the reasons that Varget does so well in 308 sized cases)
Single base powders, in general, are more consistent and ignite easier than double base powders especially in cold weather so srp are not disadvantaged. There is a corollary to this statement and that is double based powders are more difficult to ignite thoroughly than single base powders so don't use double base powders with srp in medium sized cases if low sds and consistent velocities are what you are after.
There are other differences but they tend to be open for debate whereas it's hard to argue with the statements I've gathered together and stated above.
I bought Peterson 308 cases with srp because I had many more srps than lrps, I use single based Vhitavuouri powders and do not load to DNE levels. In honesty the loads I use do not shade my 30/30 by more than around a 300 fps difference in muzzle velocity with 150 grn jktd, with the 30/30 loaded with LRP and H-LVR or CFE 223 but the accuracy difference is marked ( as you'd expect).
SRP cases are not pixie dust but they do work well with full cases of single based powders, TBH this old man can't brag about the improvement in accuracy as I'm not a particularly gifted rifleman.
So in answer to the question from my mates I always say I got nearly 6000 srps but only 2000 lrps that's why and it seems to satisfy them especially as they get to see how I shoot on the range.
FWIW economics didn't enter into my equation, for the same price per hundred for peterson unloaded brass I could have bought 140 7.62x51 (308) GGG palma 155 grn match ammo.
With all that in mind, I now return to the OP's original question, almost. I compared peterson srp loaded with 43 grains of N150 and Speer 168 match BTHP using Magtech srp v Federal brass with the same load of N150, same bullet and Magtech LRPs.
Going from a 80 year old memory, my Magnetospeed sporter chrono said the federal loads were between 25 and 50 fps quicker than the Peterson, most of the variance was from the Federal loads, the Peterson ones were remarkably consistent. Ambient temperature was around mid to high 70s and the range is at sea level almost.
As I indicated at 100 yards not a great deal of difference using my 20" barreled Browning BLR 81, I wouldn't like to call which was better. No pressure signs that I could see.
When I reloaded them in my LEE hand press I could FL resize them both reasonably easily. FWIW the Federal have over 10 reloads each the peterson brass was on its first outing. After each load the full cartridges drop into and out of my hornady headspace gauge with a little headspace showing.
For interests sake, before loading I fitted a bullet in each of the cases to the stated COAL and measured the potential capacity of both cases, IIRC the federal was about 1 grain wt of water smaller at 47.2 grains of water, a figure I recorded to use on my software to predict pressure.
Here's a vid of that measuring procedure .
Once again, IIRC, pressure prediction for both loads was in the low 50K range which suits me just fine, the velocity predictions again using my erratic memory were both around 2500 +/- and the actuals were about 50 ish higher.
I apologise for being a little vague on this issue but I no longer use those bullets, I've settled on 130 grn barnes tsx and 178 grain cast gas checked. They are quite a bit faster and quite a bit slower respectively.
