Is There a Misunderstanding

[Lapua40X]

In the Featured Content section of Accurate Shooter I've been reading 6mmBR Loading for Newbies and I wonder if I'm over cautious or if I've missed something in that piece. The author talks about loads using 100-108gr bullets, with 30.0 - 30.7 grains of Varget, saying that his match load is 30.3 Varget. He recommends starting at 29.0 grains and working up in 0.2 grain increments, checking for pressure.
Hodgdon's range of loads for the 107 grain Sierra HPBT in 6BR Remington is 26.0 to 29 grains and, while they don't get the MV that the author lists from his match experience, they don't load hotter than that for any bullet weight over 85 grains.
I have loaded my 6BR Norma above the Hodgdon 29 grains limit (the 2880 FPS MV using 30.5 grains of Varget behind a 107 gr Sierra HPBT has provided me with some very nice 5 shot groups - well under .5 at 100 yards) but I load .0015 off the lands and that load scares me just a little.
Not being critical here; just curious. Wondering if anyone has experienced pressure issues using Varget at the levels suggested in the article.

 

[CanusLatransSnpr]

What do your primers look like? Are you experiencing any heavy/sticky bolt lift with these loads? Loosening primer pockets? Shiny spots on cartridge head? If you haven't experienced any of these symptoms of over/high pressure then I would be inclined to believe that those loads are safe in "your" rifle!

Mike

 

[DennisH]

All guns take different loads. I use Varget will little issues. Nothing look scary to me.

 

[rocketron]

not 100% sure on this.

Hogdon site and the hornady reload book list it as. 6BR Rem with rem case

not 6BR Norma with lapua case

 

[fdshuster]

Most loading manual listed powder charges are on the low, conservative side. As stated, the Hodgdon Manual is a good example. Excellent starting loads, but as always, for individual rifles, it's up to the person doing the reloading to work up to whatever works safely in their rifle.

If I were the head of a large company, and publishing loading information, I would follow the same guidlines.

30 grains of Varget with 105 (Berger) to 108 gr. bullets has always been trouble-free, for me. For someone else's rifle, who knows?

 

[LHSmith]

I checked some reloading manuals, and some used Remington brass......which cannot handle the stout loads that Lapua can. I don't know how well Norma brass holds up in this chambering.

 

[shooter63]

these books are lawyer proof start where the folks on this site recommend& you will be okay this load is what i shoot in mine except mine perfers cci benchrest primers regards shooter63

 

[savagedasher]

I feel (4) factors must be known (1) case capacity overflow H2O (2) capacity displaced by seating the bullet (3) powder type (4) seating in the lands or off. Don't trust what others say start low and work up. Good Shooting Larry

 

[LCazador]

not 100% sure on this.

Hogdon site and the hornady reload book list it as. 6BR Rem with rem case

not 6BR Norma with lapua case

This is correct , 6BR Norma Lapua case has slightly larger capacity . Echo on the statement that every rifle is different ! I use 30.8g Varget with 105's .

 

[Laurie]

Nobody seems to have mentioned the biggest single factor explaining why 6mmBR loads are so much lower in the manufacturers' data - 6mm BR Remington v 6mm BR Norma.

There is such a throating ('freebore') difference between the pair that they are in effect different cartridges - and the new Berger manual in fact treats them separately. Load a 105-108gn bullet into a round where the bullet has to be seated very deeply to allow it to be chambered in the short-throat 'Remington' chamber and pressures are much higher with any given powder and charge weight than for one with the bullet seated 2/10-inch further out for the 'Norma' chamber.

Most of the factory data is for Remington chambers, only Vihtavuori / Norma / Berger providing it for the Norma version. This is partly because the Remy version precedes the Norma by a couple of decades and data has not been updated to the far more commonly used modern variant by many parties. But ... it's also partly deliberate because we have a potentially dangerous dual-specification situation here. Given all the above - and 100% correct - comments about companies who understandably play safe in this era of health & safety obsession and individuals who combine sheer stupidity with litigious leanings if / when they come to grief through their own carelessness, you can understand why the manufacturers assume the worst possible case in such applications. This is the guy who loads a 115gn bullet into a 6BR case and tries to use it in the shortest throated chamber around, one built by somebody who intended it for 200 yards bench rest with little 68gn bullets.

Both handloading and commercial ammunition manufacturing are littered with such examples, especially for older cartridge designs where the firearms and pressure specifications underwent a large change mid-life. For instance US (but not European) manufacturers load 8X57mm (7.92x57mm IS to give it the proper nomenclature) Mauser ammo at very low pressures in case somebody uses it in pre-1904 smaller bore and much weaker 7.9X57mm I specification rifles. The same applies to most handloading data for this cartridge and its 7X57mm and 6.5X55mm Mauser siblings where modern brass and rifles allow far higher pressures to be used than the 45,000 psi or so 19th century loads safely. Likewise, all .45 Long Colt ammunition is loaded in a low pressure form to suit 19th century Peacemaker single-action revolvers, all high-performance loads intended for rifles and stronger more modern revolvers withdrawn on safety grounds many years ago, and the .45-70 Govt is loaded to suit Trapdoor Springfields. .44-40 WCF had two loads on sale for generations - a low pressure revolver loading and a 'high-velocity' rifle load (originally developed pre World War 1 for the M1892 Winchester levergun). The latter was withdrawn by the ammunition manufacturers sometime in the 1950s or 60s (I think) because idiots kept using it in weak 19th century revolvers despite specific warnings on the ammo cartons not to do this.

 

[savagedasher]

That is correct I use Quickload and I change H2O setting their is one full grain difference.
Good Shooting Larry

 

[Lapua40X]

Wow!!! You guys ought to get together and write a Reloading the 6BR for Newbies #2 with some of this info. I knew about the hard opening bolt, overly conservative data to protect against certain liabilities and flattened primers but that technical data of differences between the 6BR chamberings and brass cleared up a lot of the questions in my head. I had not been able to find specific data that had separate specs. for the 6BR Remington and 6BR Norma loads.
Thanks to all of you for your input.
I weigh my loads twice but, at 30.5 grains of Varget in the Lapua case with a 107 gr. Sierra HPBT in my 6BR Norma my primers look OK but, once in a while, I experience a bit of difficulty with bolt opening on the fired round. For that reason I feel I need to back down .25 grains and I'll do that next trip to the range.
Thanks again for clearing up some of the fog in my life.

 

[savagedasher]

30.1to30.3 of Varget in most guns are normally are very good. I have found different lots of powder don't shoot the same. Good Shooting Larry