6.5 Creedmoor.......Large or Small primer pocket???

[6.5 forever]

CCI 450, H4350

 

[Laurie]

CCI 450, H4350

Not surprised - the Australian made Hodgdons seem to work well with small primer ignition. Sadly we can't get them in Europe any more thanks to EU health & safety regulations.

IME, some Viht powders work very well indeed with SP ignition, others not. Viht N150 is near universal here in 308 F/TR with heavy bullets and SP brass for instance, but I'd use large primer as first choice for its N140 stablemate and when I tried N555 in 7mm-08 (reformed 308 SP), it was inferior to standard Lapua LP brass. Hodgdon CFE-223 in 308 Palma was a complete bust - hangfires and the odd misfire, but oddly the much older H414 ball powder from the same factory actually performed better in a cold weather test in Palma brass, the opposite of what is always said about this type needing more aggressive ignition.

 

[6.5 forever]

Not surprised - the Australian made Hodgdons seem to work well with small primer ignition. Sadly we can't get them in Europe any more thanks to EU health & safety regulations.

IME, some Viht powders work very well indeed with SP ignition, others not. Viht N150 is near universal here in 308 F/TR with heavy bullets and SP brass for instance, but I'd use large primer as first choice for its N140 stablemate and when I tried N555 in 7mm-08 (reformed 308 SP), it was inferior to standard Lapua LP brass. Hodgdon CFE-223 in 308 Palma was a complete bust - hangfires and the odd misfire, but oddly the much older H414 ball powder from the same factory actually performed better in a cold weather test in Palma brass, the opposite of what is always said about this type needing more aggressive ignition.

I tested N555 and was happy with it. But at the time its cost was higher than Hodgdon. Also my test was in the cold months.

 

[Laurie]

As always, it's always important to try things out, but for SP larger-capacity cartridge brass applications it seems to apply even more due to the reduced ignition effort. However, I'm not unduly surprised it worked well for you in the 6.5mm Creedmoor. In the UK, Lapua SP 6.5CM brass arouses both praise and dissatisfaction. I reckon it works well for most users, but some have found it unsatisfactory with their choice of primers and powders.

Here's my report on N555 in both types of brass against H4350 in a 7mm-08 with minimum SAAMI chamber dimensions and longer than SAAMI freebore.

https://www.targetshooter.co.uk/?p=3683

 

[xswanted]

I'm having a 6.5 Creedmoor built for 1000yds and going to be reloading for it. Looking at brass, I've noticed large and small primer pockets are available.

What are the advantages and/or disadvantages of one over the other?

Thanks!

Strictly a target rifle?

If so I’d go with small as long as you don’t plan on shooting in cold (sub 20 degree f) temps.

Better primer pocket life if you’re running warm loads.

 

[BowChamp]

we have a couple factory Rem 700s that we use Lapua LRP brass in just to keep from worrying about blanking a primer,,

I've seen this mentioned before. Something I will keep any eye on.

Thanks

 

[BowChamp]

Pros for SRP ignition:

Reduced velocity SD values with an appropriate primer/powder match.

More metal in the case-head = greater strength / longer life. (Or for some, being able to ramp up pressures / MVs to higher levels than standard large primer equivalents.)

Primer supply availability issues - can work either way of course.

Downsides:

Marginal ignition heat and brisance in Creedmoor / 308 size cases makes the SRP type:

..................... powder and primer sensitive (large MV spreads, even hang and misfires with some combinations)

..................... ambient temperature sensitive. (Cold components need more primer flame heat to reach consistent ignition temperatures.)

................... reduced MVs compared to LRP. Usually a small reduction but can be as much as 1.5gn difference in powder charge. (If using both types, loads usually need working up separately at the top end of charges.)


Then too .................. severe primer cratering and in worst cases blanking as @Eric Leonard says - a rifle, not excessive pressure, problem. I had an FN SPR (selected Win 70 pre-64 type action) I rebarrelled to 6.5X47 Lapua and had to have it rechambered to 260 Rem to return to LRP. For some reason small primers suffer this worse than large. The other answer is a bolt / firing pin job turning the pin down and fitting a bush with smaller aperture in the bolt face - wasn't an available service in the UK when I had the SPR. Affects many off the shelf factory rifles.

Finally, there can be a serious risk in transferring a 'hot' maximum load charge from SRP to equivalent LRP when both types of brass are available, where the case is weaker and the more aggressive primer increases pressures substantially.

Thank you for the breakdown!

 

[BowChamp]

As I said if you are pushing it to max pressures then yes you will get more with SRP but no real need but I know some do that. Shooting 140s in the 2750fps range is a mid range load and brass will last but if people are trying to push 140s at 2850+ then yes it will kill brass faster.

I don't really have a velocity expectation. Going to look more for accuracy and velocity will be what it is...within reason of course.

 

[BowChamp]

Strictly a target rifle?

If so I’d go with small as long as you don’t plan on shooting in cold (sub 20 degree f) temps.

Better primer pocket life if you’re running warm loads.

Yes Sir.....no hunting, just target shooting. Having this one built just to enjoy shooting it.

 

[Rob01]

I don't really have a velocity expectation. Going to look more for accuracy and velocity will be what it is...within reason of course.

Either will work for you if looking for accuracy. Will come down to load work up. Just don't want you to think SRP are some magic pill.

 

[BowChamp]

Either will work for you if looking for accuracy. Will come down to load work up. Just don't want you to think SRP are some magic pill.

Gonna start with large primer brass because the range is littered with once fired brass. I've been 4 times now and picked up about 400 cases already. It appears no one reloads anymore...LOL!!

I'll eventually try some small primer brass just to see for myself.

Not much of a believer in magic pills....

Thanks!

 

[spudgun]

Starline brass makes both large and small primer brass.

I have been using Starline SRP brass for 6 years now. Have very few issues with case neck split and primer pocket getting large.

I have annealed the brass when I notice neck splitting and have 50+ reloads on the brass (over 6 years).

Case and primer pocket issues are less than 4%.

 

[Old Navy]

I just retired a 6.5X47 barrel at 1800 rounds. The barrel was still good but the Lapua brass started showing signs of case head separation at 18 firings. Some of the primers were getting easy to seat. The load was 142 SMK/140 Berger VLDs over 40.5 grains of H4350 over CCI-450s. 2830 fps.

 

[Steve Donlon]

Starline brass makes both large and small primer brass.

I have been using Starline SRP brass for 6 years now. Have very few issues with case neck split and primer pocket getting large.

I have annealed the brass when I notice neck splitting and have 50+ reloads on the brass (over 6 years).

Case and primer pocket issues are less than 4%.

I just got some 6.5 Creedmoor LRP Starline brass and thought it would be more like Horrnady or Sig brass but it's almost like Peterson by weight. Have not reloaded any yet. You are brave to reload so many times amigo.

 

[spudgun]

I just got some 6.5 Creedmoor LRP Starline brass and thought it would be more like Horrnady or Sig brass but it's almost like Peterson by weight. Have not reloaded any yet. You are brave to reload so many times amigo.

I do check my brass after I clean it. If I see something funny I will toss it. The biggest issue is a split neck., which I relate to not annealing the brass enough.

But I find very little issues with the brass. I do not shoot a hot load, keep it under 2700 FPS.

 

[Rob01]

I just retired a 6.5X47 barrel at 1800 rounds. The barrel was still good but the Lapua brass started showing signs of case head separation at 18 firings. Some of the primers were getting easy to seat. The load was 142 SMK/140 Berger VLDs over 40.5 grains of H4350 over CCI-450s. 2830 fps.

Why would you stop using a good barrel because your brass went bad? Just get more brass.

And you only buy 100 pieces of brass for a barrel?

 

[Old Navy]

Why would you stop using a good barrel because your brass went bad? Just get more brass.

And you only buy 100 pieces of brass for a barrel?

To answer the first question. At about 1600 rounds I took the throat out another .173 just to keep the heel of the Hornady 140 &147s ELD-M in the neck. The only other bullet I could shoot with this throat was the 142 SMK. It was just an experiment. I could safely push the 147 over 2800 with .5 MOA accuracy. When the brass gave up I had my son rechamber the barrel to 6.5 CM. I played with it for 200 rounds with only fair results.

I am an informal BR target shooter. 100 pieces of brass has always been enough for me. I shoot Savage model 12 BR rifles and one switch barrel custom. I usually get bored with one cartridge before I wear the brass out. I do have 200 for my 6 BRA because I shoot it a lot.

 

[spudgun]

To answer the first question. At about 1600 rounds I took the throat out another .173 just to keep the heel of the Hornady 140 &147s ELD-M in the neck. The only other bullet I could shoot with this throat was the 142 SMK. It was just an experiment. I could safely push the 147 over 2800 with .5 MOA accuracy. When the brass gave up I had my son rechamber the barrel to 6.5 CM. I played with it for 200 rounds with only fair results.

I am an informal BR target shooter. 100 pieces of brass has always been enough for me. I shoot Savage model 12 BR rifles and one switch barrel custom. I usually get bored with one cartridge before I wear the brass out. I do have 200 for my 6 BRA because I shoot it a lot.

I did the same thing on my 6 CM barrel. Since it was 28" long, I took it off and had my gun smith cut and rechamber the barrel and re crown it. Shoots just as good as before and saved me $400.00 for a new barrel.

 

[Rob01]

I did the same thing on my 6 CM barrel. Since it was 28" long, I took it off and had my gun smith cut and rechamber the barrel and re crown it. Shoots just as good as before and saved me $400.00 for a new barrel.

Only problem is barrel life is not as long as the original on a set back. Usually about a little over half. I did one once but never again.

 

[JMAN80]

If you have piles of LRP run those but most people use SRP with BR4 primers.