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ball powders and magnum primers
Kari Prager
Member Posts: 67 ✭✭
Does anyone have an opinion (of course you do!) on the use of magnum rifle primers with ball powders such as H 380 or H414?. I have recently read conflicting reports on the need for magnum primers with these powders, but in the past have always used regular rifle primers with no apparent problems (one exception: CCI BR primers). What does the collective wisdom of the group say? Thanks to all,
Kari
Kari
Comments
Kari
If this wasn't the direct question, those powders have been recommended for using a magnum primer, as have other powders, in the winter months to attempt to stabilize cold weather performance using the same powders as in the hot summer. the drawback here is making sure all your 'winter' ammo gets shot before summer.
If that is the case I recommend going to Hodgdon extreme powders or Vihtavuori that are more consistent from summer to winter. then you won't have the super high pressure problems from winter to summer for loads.
I am going to buy some magnum primers today and load up a bunch of H414 - of course accuracy is a little bit relative compared to your rifle since I am shooting a K 31 Swiss with target sights. Still, it is accurate enough to tell the difference between good and not so good. Another gentleman made the point about temperatures and primer choice. Even though I live in California, it's usually about 40 degrees at the range where I shoot. So that's another reason to favor the magnum primers.
I tried to go shooting in the snow on Monday, but they closed the road to the range on me!
Kari
my experience with ball powders suggests two things.
First it has a lot to do with the type ball powder (H-110 very hard to light)your planning to use.
Second it has a lot to do with the case size your reloading.
As an example H-414 in a 22-250 is going to prefer a magnum primer, but use the same powder in a case like 222 and standard primers might work O.K.
Your doing the right thing: select a charge weight and bullet. load all rounds the same except for the primer. Make several ten round batches with every primer you might consider using and then go shoot some paper from a rest. The better the rest the less human error!
Keep the load that shoots the best and fine tune from there![8D]
I am using fairly large cartridges, about .308 size or a little larger, so the magnum primer should work pretty well. And 414 looks like a good powder for this size.
Waiting for the snow to melt so I can go try it,
Kari
There are some comments to make about Ball Powders in general:
- They are Double Base powders (Nitrocellulose + Nitroglycerin)
- They are degressive in burn characteristics, the surface area decreases quickly as the surface area is reduced.
- They are very uniform in thrown charges.
- They are very high density due to the size and shape of the grains.
- They are chemically stable and have a long shelf life.
- Bore erosion is considered to be low.
- But the fouling residue can be obnoxious and difficult to remove.
- They can be difficult to get ignited.
The two big reasons that Magnum primers have been recommended are:
1) Because of the coatings used on the individual grains that control the burn characteristics (deterrents), the graphite for static control and the coating used to control muzzle flash.
2) The density of the powder as it sits in the case. There are very few air spaces in between the grains so it gets packed tightly.
The powder manufacturers have made huge strides in developing new and better products as well as correcting some of the problems that we encountered with older products. Ball Powders have received a few of these improvements which have allowed us to move away from the hard and fast rule of using only Magnum Primers. I think that the companies manufacturing primers have made improvements in the consistency of their products as well.
The only drawback to Ball Powders that I have experienced is the density of the loads that I use. Some have been troublesome to ignite with standard energy primers. High energy primers provide the necessary intensity to get the ball rolling.
I don't want to create any problems for you or your testing but I suggest rethinking your selection of H414 as your powder of choice. Your case is closer to the capacity of the 30-06 than the .308 by several grains. The maximum loads that I've worked with for H414 do not come anywhere near to filling the case. These loads allow the powder to shift significantly and you can experience positional sensitivity, the pressure curve changes.
I like to use a powder that fills the case to the base of the bullet or as close to it as possible while still remaining at safe working pressures. I like XMR-4350 and IMR-4350 with loads that don't exceed the G11 pressure level of 45,500 PSI.
If you haven't seen this website already, it's worth a look and some reading:
http://www.swissrifles.com/index.html
Best.
Many thanks for the time you spent on that post, Kari
Having gone back after the fact and read some more on this post I'll give you my two best loads for that rifle. 43 gr. of VV N150 and a standard primer and 46 gr. of VV N160. Both give right around 2600 fps with a 168 Nosler CC. Or, knock off one grain for a Sierra 175 Matchking. Same velocity but better ballistics. These loads will typically out shoot the standard GP11 ammo that I bought a ton of @$2.99 a ten round box. One thing I found with this caliber, especially in the K-31 is taking loads up near max is really counter-productive to the accuracy that can be had with it.
Also of note, are you full length resizing them to standard GP11 dimensions? Or are you sizing them back to K-31 dimensions. Big difference there. The K-31 case should measure .470 at the shoulder when it's fired. The standard 7.5x55 dimension is .455". That is a lot of movement you don't have to make if you don't want to. Redding makes a sizing die for the K-31 chambers, #91235. If you have any questions, see if you can contact Bruce Merkur there and he will set you straight. He probably wouldn't remember me from Adam but he does know the guy who I buy from at the Gunstop. Way back when I first started reloading for this caliber I was trying to fully resize to standard with Hornady dies. It was brutal to say the least. Both they and RCBS wanted a lot of money for a custom die. Redding's die was already made and was around $40.00. -hope that helps.
Apologies for being so late in replying. Thanks for the load information! I tend not to load hot, so we are in agreement there. I have been sorting cases by rifle and neck-sizing only,
do you think this will cause any problems? It hasn't seemed to so far and I have shot hundreds of rounds through these rifles. Of course I trim occasionally but not frequently, as it has not been necessary.I am going to try your loads, I have a lot of 168 gr. bullets. I have also had good luck and good groups with Sierra 150 gr spitzers. Thanks again for your informative post.
Kari