shooter177
CGN Regular
- Location
- Durham region
I assume the 308 palma chamber is designed to shoot the 155g pills, but what is the difference between it and a 308win ?
308 Palma chamber
- Thread starter shooter177
- Start date
- Location
- Somewhere on the Hudson Bay Coast
The following is in response to the same question on Reloader's Nest:
As a former US Palma Team member, perhaps I can shed some light on this subject.
About 1980, the host country stopped supplying the rifles. In 1976, the World Palma Championships were held in Camp Perry, Ohio, and Winchester Model 70 Target Rifles were supplied. However, the host country has always supplied the ammo; in 1976 the USA supplied M118 Lake City Match. Some of the lot would be sent to each participating country the year before the match so chambers and barrels could be made to shoot it very accurate. This is because most countries do not allow handloads for highpower competition and arsenal or commercial ammo is used.
A Palma chamber is typically one that has dimensions virtually equal to the USA SAAMI specs except for the leade or throat. Leade diameter is usually .001-inch larger in diameter than the bullet. Some 30 caliber bullets used prior to the 1992 World Championships were as small as .3070-inch and .3065-inch groove diameters were best for accuracy. Since 1992, the International Palma Committee has specificied the Sierra Bullets 155-gr. Palma bullet be the standard and these are sent to the host country for loading. Length of the chamber leade or throat is usually short enough to allow about .010-inch setback of the bullet when chambered. It's interesting that 4-groove barrels shoot these bullets more accurate than a 6-groove one.
In Palma matches in the USA, Sierra's Palma bullet must often be used, but it can be handloaded. Other bullets and weights are sometimes allowed in local Palma matches.
As a former US Palma Team member, perhaps I can shed some light on this subject.
About 1980, the host country stopped supplying the rifles. In 1976, the World Palma Championships were held in Camp Perry, Ohio, and Winchester Model 70 Target Rifles were supplied. However, the host country has always supplied the ammo; in 1976 the USA supplied M118 Lake City Match. Some of the lot would be sent to each participating country the year before the match so chambers and barrels could be made to shoot it very accurate. This is because most countries do not allow handloads for highpower competition and arsenal or commercial ammo is used.
A Palma chamber is typically one that has dimensions virtually equal to the USA SAAMI specs except for the leade or throat. Leade diameter is usually .001-inch larger in diameter than the bullet. Some 30 caliber bullets used prior to the 1992 World Championships were as small as .3070-inch and .3065-inch groove diameters were best for accuracy. Since 1992, the International Palma Committee has specificied the Sierra Bullets 155-gr. Palma bullet be the standard and these are sent to the host country for loading. Length of the chamber leade or throat is usually short enough to allow about .010-inch setback of the bullet when chambered. It's interesting that 4-groove barrels shoot these bullets more accurate than a 6-groove one.
In Palma matches in the USA, Sierra's Palma bullet must often be used, but it can be handloaded. Other bullets and weights are sometimes allowed in local Palma matches.
lejarretnoir
CGN Ultra frequent flyer
- Location
- 162km from Connaught
For the most part it's a different throat usually shorter, next to zero freebore or little and various lead angles for different Palma bullets. I agree with Boomer as to tighter bores and 4 grooves. They do shoot better. The Mclennan .3075 13" twist 4 groove I have is very accurate.
The one reamer I have can load Palma bullets where they seat just short enough to load into a magazine and still touch the lands.
The one reamer I have can load Palma bullets where they seat just short enough to load into a magazine and still touch the lands.
155 Sierra's are no long required. At the time of that write up, Sierra may have been the only 155 gr bullet. Any bullet under 156 gr is allowed. I believe the Canadian Palma Team is going with 155.5 fullbore Berger's for the next Palma.
Maynard is correct. Canada's team will be shooting Krieger barrels, chambered with a reamer of their own design, and like most TR/Palma shooters using bullets with short bearing surfaces, they are using "palma" bores. The most common configuration is 0.298" X 0.3075". 13 and 14 twists are the most common twist configuration too.
ICFRA rules specify a maximum bullet weight of 156 grains and no brand is specified. Canada will be using the Berger 155.5 "Triple Nickle" bullets
ICFRA rules specify a maximum bullet weight of 156 grains and no brand is specified. Canada will be using the Berger 155.5 "Triple Nickle" bullets
If the responses seems a bit overexplained, the simple answer is- it's just a 308 chamber w/ some measurements carefully controlled to optimize the performance of a specific 155 bullet. It's generally tighter than SAAMI spec, but should not require neck turning for most .308 brass. You probably will need to full length resize cases to make them fit.
I have read the current Canadian chamber description. It is just a simple variation of a 308 Palma chamber with reamers from a company that has a habit of making reamers that do not cut what the print says. Nothing close to rocket science. If Canada wants to win then to start they need to look at what the Brits did in the last Palma, simple in many ways. Just my opinion, as usual, your mileage may vary.
The CDN Palma reamer is not so tightly wrapped up, I have chambered with it. It is just another reamer, not something magical but it was designed for the ammo that will be used. I like my reamer and throater better. The Brits are a professional team, they do not pay the bills like the Canadian team members. If you want to beat the Brits, you need to put in the dollars and training time that they do, simple.
Rob, I have been asked by the commandant of the team not to discuss their reamer specs. I have seen the drawings and I agree that its virtue is matching their ammo.
You also nailed it with team funding, however when you have over 4000 kms separating Canadian team members, and only a handful of long enough ranges on which to practice, our geographical circumstances are quite diffferent.
It is straying off topic, but there is also a terrible inequity in the degree to which different disciplines are financially supported. TR is pretty flush compared to what is given to F-Class.
You also nailed it with team funding, however when you have over 4000 kms separating Canadian team members, and only a handful of long enough ranges on which to practice, our geographical circumstances are quite diffferent.
It is straying off topic, but there is also a terrible inequity in the degree to which different disciplines are financially supported. TR is pretty flush compared to what is given to F-Class.
