Primer Pocket Size???

[Hoekight]

I’m working on a 25-308ai project I’ve dreamed about since I started reloading. It’s nothing new but it’s new to me and I got to put my spin on it. I worked out what I wanted with Nathan from JGS and I really enjoyed that process. While I’m waiting for my reamer to be ground I’ve been gathering up the rest of the pieces.

I’m kinda up in the air about srp/lrp brass. I have Lapua 308 Palma brass and some srp Peterson brass in 308. I know it’s a pretty big chore to neck it to 25 cal and I don’t mind the labor at all. I actually enjoy that kind of stuff that many people dreads. But there are other easier options like 243 brass that would only require a mandrel to size it up. Would it be best to size down the Palma brass with the small pockets or use Lapua 243 brass with large pockets? Or get Peterson srp 243 brass to neck up. (Peterson has worked well in a couple of my 6br rifles) Opinions seem to be a dime a dozen on the issue and every forum I read about it gets off topic on about the 4th post.

Aside from the srp handling over pressuring better, will you leave anything on the table with accuracy or consistency, one vs. the other? I’m not shooting in the cold, I’m in FL so cold powder ignition wouldn’t be an issue. Just looking for a little advice from some with hands on experience. Sorry to beat the dead horse of primer size but I either shoot a PRCW or a BR….. not much in between in the target world.
Thanks in Advance .
Dwayne

 

[10XSHOOTER]

Using a .308 case and Acklleyizing it. You will be shooting over 40 grs of powder.
LRP to lite that much powder off!

 

[Hoekight]

Using a .308 case and Acklleyizing it. You will be shooting over 40 grs of powder.
LRP to lite that much powder off!

Every FTR shooter I know is shooting Palma brass in 308’s with 42-44 grains of N150. I’ve never seen one of them have ignition problems. I guess that’s why I don’t understand the small vs. large primer debate.

 

[Sandstorm]

Its not a problem to use small primer.
CCI450 is it.

 

[Walt Krafft]

Necking down might make your necks too big and require turning. Necking up is easier. What neck size did you spec your reamer? If you are losing brass to loose primer pockets, your load is over pressure imo.

 

[Hoekight]

@10XSHOOTER i Hope I didn’t come across as being sarcastic. Just stating my lack of understanding. The stuff I read where the lrp brass is thought to be needed in cases in or over the 40+ grain capacity makes me question how TR shooters gets away with it.

 

[Hoekight]

@Sandstorm thats the primer I would start with as I already use them in several of my BR’s.

 

[Hoekight]

Necking down might make your necks too big and require turning. Necking up is easier. What neck size did you spec your reamer? If you are losing brass to loose primer pockets, your load is over pressure imo.

I set the reamer to need to turn necks. Figured if I necked down it would be a must anyways. .285 for the reamer. Most of the brass I measured was .014 -.015. So ..285 I would need to turn to .281 for .004 clearance which would be .012 neck thickness on whatever brass I use.

 

[Truckbed]

I cannot speak with experience to the topic of your post, but I am in the final stages of having a 6x47 L ready to go , so I’ll follow this with interest. I’d like to do a 25x47, being a quarter bore fan. The 25x47 would definitely be used in some cold weather deer hunting, so I would want a SRP to ignite just about 40gr of powder.

Were it me I’d mandrel-up since it’s only a one caliber hop, versus takin’ her down multiple calibers. Looks like you’d be fire-forming to get the Ackley shoulder either way. Should be a fine chambering ! Wouldn’t cost much to get a mandrel or two and a batch of some quality 243 brass…..try it both ways….then YOU will know!

 

[243winxb]

7mm-08 brass.

 

[Hoekight]

Were it me I’d mandrel-up since it’s only a one caliber hop, versus takin’ her down multiple calibers. Looks like you’d be fire-forming to get the Ackley shoulder either way. Should be a fine chambering ! Wouldn’t cost much to get a mandrel or two and a batch of some quality 243 brass…..try it both ways….then YOU will know!

I’ve about decided to just get both and see what works best for my setup. Don’t seem to be a real answer.

I almost went the 25x47 route but I love a 308 case for some reason and I wanted to play with a reamer print. So here I am trying to make an educated “guess” as which brass I should use.

 

[Bill Norris]

@10XSHOOTER i Hope I didn’t come across as being sarcastic. Just stating my lack of understanding. The stuff I read where the lrp brass is thought to be needed in cases in or over the 40+ grain capacity makes me question how TR shooters gets away with it.

I almost exclusively use the CCI-450 M SRP in my 260AI and sometimes the load will be @ 47.0 gr. or a tad more. I find better E S #s than with the LRP and so far have not experienced any issues in the colder temps. here in S E N C. I suppose in other areas of the country where temps. drop considerably lower than here there could be some issues.

 

[10XSHOOTER]

@10XSHOOTER i Hope I didn’t come across as being sarcastic. Just stating my lack of understanding. The stuff I read where the lrp brass is thought to be needed in cases in or over the 40+ grain capacity makes me question how TR shooters gets away with it.

They are mostly shooting in warmer tempertures. Are they really getting good ignition with the small primer? With a large primer you will get proper ignition!

 

[Robert Weidler]

I’m working on a 25-308ai project I’ve dreamed about since I started reloading. It’s nothing new but it’s new to me and I got to put my spin on it. I worked out what I wanted with Nathan from JGS and I really enjoyed that process. While I’m waiting for my reamer to be ground I’ve been gathering up the rest of the pieces.

I’m kinda up in the air about srp/lrp brass. I have Lapua 308 Palma brass and some srp Peterson brass in 308. I know it’s a pretty big chore to neck it to 25 cal and I don’t mind the labor at all. I actually enjoy that kind of stuff that many people dreads. But there are other easier options like 243 brass that would only require a mandrel to size it up. Would it be best to size down the Palma brass with the small pockets or use Lapua 243 brass with large pockets? Or get Peterson srp 243 brass to neck up. (Peterson has worked well in a couple of my 6br rifles) Opinions seem to be a dime a dozen on the issue and every forum I read about it gets off topic on about the 4th post.

Aside from the srp handling over pressuring better, will you leave anything on the table with accuracy or consistency, one vs. the other? I’m not shooting in the cold, I’m in FL so cold powder ignition wouldn’t be an issue. Just looking for a little advice from some with hands on experience. Sorry to beat the dead horse of primer size but I either shoot a PRCW or a BR….. not much in between in the target world.
Thanks in Advance .
Dwayne

I developed my 25-08 AI about three years ago and spent a lot of time and money trying to get a 3000 fps load. This was doable but groups were not up to snuff. Finally settled on 2900 fps using (47.0 g) VV N560. Results were much better. Have always used Lapua LRP brass in 243 with no ill effects or problems. Bullet of choice is Berger 135g LRHT. H4831 is an alternate powder but the VV performed better for me. The N560 load is about a 96% fill. Plenty of room to go up or down some. For fire forming I used 42 grains of H100V and a Speer 120 g bullet (much cheaper). This gave good results. My gun is a KRG Bravo chassis, Bartlein barrel with Heavy Palma contour and 5R rifling cut to 28 inches

I hope you have as much fun with yours as I have had with mine. Note: when fireforming shoot 5 shot strings and let the barrel cool between strings. I burned out a barrel shooting too many too fast.


5 shots at 200 yards, 0.303 moa, 1 inch dot

 

[Evan]

My 6.5x47 gets erratic when it’s cold. In winter when it’s around 0 degF, velocity becomes erratic and there is noticeable delay between pin fall and the bang.

 

[Hoekight]

I hope you have as much fun with yours as I have had with mine. Note: when fireforming shoot 5 shot strings and let the barrel cool between strings. I burned out a barrel shooting too many too fast.

I developed my 25-08 AI about three years ago and spent a lot of time and money trying to get a 3000 fps load. This was doable but groups were not up to snuff. Finally settled on 2900 fps using (47.0 g) VV N560. Results were much better. Have always used Lapua LRP brass in 243 with no ill effects or problems. Bullet of choice is Berger 135g LRHT. H4831 is an alternate powder but the VV performed better for me. The N560 load is about a 96% fill. Plenty of room to go up or down some. For fire forming I used 42 grains of H100V and a Speer 120 g bullet (much cheaper). This gave good results. My gun is a KRG Bravo chassis, Bartlein barrel with Heavy Palma contour and 5R rifling cut to 28 inches

I hope you have as much fun with yours as I have had with mine. Note: when fireforming shoot 5 shot strings and let the barrel cool between strings. I burned out a barrel shooting too many too fast.

View attachment 1711536
5 shots at 200 yards, 0.303 moa, 1 inch dot

Thank you for the advice. It should be fun.

 

[Hoekight]

I almost exclusively use the CCI-450 M SRP in my 260AI and sometimes the load will be @ 47.0 gr. or a tad more. I find better E S #s than with the LRP and so far have not experienced any issues in the colder temps. here in S E N C. I suppose in other areas of the country where temps. drop considerably lower than here there could be some issues.

Thank you. That’s the way I’m leaning too. I’m in FL and don’t plan on shooting in the cold.

 

[358WCF]

I've been spiballing a similar project for a couple of years. Maybe just a 25 Souper. Why not use 260 Rem. brass? It's only a .007" reduction. Lapua & other premium manufacturers make it, maybe even in both small & large primer size. Just a thought.

There's only 2 SP cartridges in my arsenal, so the LP inventory is significantly heavier. It doesn't get very cold around here, but still thinking LP will be how I'd go if given a choice.

As always YMMV

 

[Straightshooter1]

I almost exclusively use the CCI-450 M SRP in my 260AI and sometimes the load will be @ 47.0 gr. or a tad more. I find better E S #s than with the LRP and so far have not experienced any issues in the colder temps. here in S E N C. I suppose in other areas of the country where temps. drop considerably lower than here there could be some issues.

They are mostly shooting in warmer tempertures. Are they really getting good ignition with the small primer? With a large primer you will get proper ignition!

I shoot exclusively in warm to hot temperature using SRP's for my .308 using as much as 44 grs of powder and they perform excellently. In fact, I tend to get much better results with them than I do with the LRP's. But none of my loads with SRP's have been with any ball powder. I suspect loading 44 grs of a ball powder might present an issue more than it does with stick powder???

 

[varminter65]

I set the reamer to need to turn necks. Figured if I necked down it would be a must anyways. .285 for the reamer. Most of the brass I measured was .014 -.015. So ..285 I would need to turn to .281 for .004 clearance which would be .012 neck thickness on whatever brass I use.

Necking down is the way to go I have found after working with this cartridge for more than 10 years, if you neck up from 243 you will always end up with very short necks after fire forming, not good. I think it is a great cartridge even though I have only worked with 10 twist barrels so lighter bullets.