Just tried to find a load for the Nosler 125gr. partition using H4350. From the Nosler manual, I started out at 44gr. and worked my way up to 47gr. max. All but the 44gr. load showed flattened primers, with the 46 and 47gr. both showing cratered primer strikes. Is this always a sign of high pressure? I was trying to get this M70 Featherweight somewhere on the ballistic tables, maybe 2800fps if lucky, but the chrono showed 2750 for the second two loads and 2830 for the last... Groups all within 1-1.75". Maybe I just need to stay with the 140gr. at 2400fps. Hoping for a bit better trajectory for the power-line right of way shots. Any ideas? Ideally I'd like to find one great load and stick with it, practice with it, etc. Thanks, Mike.

Some rifles (like my new Savage 12BVSS) show the primer "cratering" with all sorts of loads. That's a sign of space between the firing pin and the firing pin hole in the breech.

Cratering could be the sign of a weak firing pin spring.

But if the primers were flatened and cratering, what in the he@!#%$%& did you keep going for?

Get it checked before you bleed!

As jack would say, "end of rant".

Mike

This is what I would do:

1) Overload that M70 until the bolt has to be pounded open with a soft mallet.

2) Reduce the load until the brass has long life.

3) Note the charge difference between the cratering load the above two loads. If there is not 6%* of safety margin then there is a chance that one of the above may happen. If there is more than 6%*, then the cratering is not a pressure sign.



* a hot day, hot chamber, heavy case, hot powder lot, heavy bullet, seating depth error, powder measuring error, dirty chamber, dirty throat, hot primer, dirty reloaded case, fat bullet, and anything else can add up to 6%.

First, try switching primers. Some such as Federal seem to have a softer primer cup then CCI which, to me seems to have the hardest primer cup.

Secondly you may have a tight bore on your rifle. I had a .22-250 that would shoot like a house afire, however I could never get velocities beyond that of my .223. I had two choices, rebarrel or sell the rifle. I gave the rifle away.

Mike , I have a model 70 6.5x55 and have played around quite abit with loads . Havent used the 125 nosler yet though.

I like R22 and R19

Ive used 4350 and 4831 , but got tighter groups with R22

Ive loaded 48 gr R22 with nosler 140 with good results , But I will back of alittle to 47 47.5 gr for longer case life

129 gr hornadys and 49 gr R22 works good , 48 gr for good case life

120 gr bullets ive used 50 gr R22

I just loaded some new brass for my new scratch built swede mauser sporter.
120 sierra with 47 gr R19 and 48 gr R22

I use norma and lapua brass ,win. primers

Rick

[ 11-30-2003, 07:33: Message edited by: GSP7 ]

Thanks for the replies. The bolt lift was easy for all shots fired. I have run into the hard bolt lift situation before with my 700, and stopped there and pulled the rest of the bullets, but didn't notice the primer flattening on these until later. Guess I'd better work on my situational awareness. As far as this being a slow rifle, so far every load I have tried has been 100-200fps lower than published loads with similar length barrels, but it shoots well and has accounted for a number of deer. Guess I shouldn't complain too much. Mike.

Nosler Partitions are a fairly hard bullet to form to the rifling. They will tend to give slightly higher pressure, and sligthly higher velocities than normal bullets do, for the same load. You generally have to back down half a grain to a grain if you're using Partitions.

When loading for the 6.5x55, you have to be very careful about which reloading data you use. Some data is for modern firearms, and some is for the Swede milsurp. Give or take some Kentucky windage, a modern arm should take at least a grain, maybe two more than the milsurps.

Since you are chronographing, graph your MV vs Charge, with charge on the horizontal axis. The increase in MV will be linear, and then start to flatten out. Eventually, you will reach the point that increased charge gives practically no increase in MV. However, pressure has continued to increase with increasing charge. You cannot operate very far into the part of the MV curve where it stops being linear.

I've had very good luck with my Swede, using H4350, AA4350, and RL22. Of course, I get to pack 29" of barrel around, too....

Good luck... it's a delightful cartridge. I'm sure you'll enjoy it. I hope this helps a little.

Mike...

We were posting at the same time.

According to Hodgdon, most rifles run about 70 fps slower than published. Test barrels are cut to the minimum side of SAAMI specs, and produce more pressure for the same load than an average rifle. If your rifle is 100 fps slower, it's actually pretty close to the mark.

This may be contributing to your problem---Maybe not. All the American made brass for the 6.5 x55 that I have is undersize. The only reloadable boxer primed brass that is not undersized came from Yugoslavia in the early 90s.
If your bolt handle lifts easily That rifle isn't getting ready to send you to heaven. Your questions to this knowlegable forum were well founded, however. roger

Roger, Denton, again thanks.
The brass I used is from Federal, but I also have some Remington, Winchester and PMC. I am also familiar with the "no more velocity with increased charge" situation. The last time I saw that was loading RL-22 with the 140gr. I figured I ran out of barrel with the slow powder.
I guess I'll start again, different brass, primers, and along with a lower starting charge, smaller increments of increase. Mike.

For what it's worth, I have a Remington 700 Classic in 6.5x55. This is a pretty strong action. I get 2875fps with a Sierra 120gr HP, 2815fps with the Hornady 129gr PSP. I don't usually shoot anything much heavier because of the 1 in 9" twist in this rifle. Neither load approaches max, but I use VihtaVouri 550 and 560 powders. Most of the loads listed for this caliber are overly mild because of all the military m96 mausers that are still out there. If you're using a commercial action like a Winchester I don't see how you could be having severe pressure problems. I'd have a gunsmith check it out. Best wishes.

Cal - Montreal

Mike, I have a CZ 550 American with a 23" tube. The max load listed, 51.5 gr of RL-19 with the Barnes 120 gr XLC (Barnes manual) gives me right at 3090-3100 fps, no pressure signs at all, and 5 shot groups that run 1/2-3/4" at 100 yds. I tried some 125 Part.....good bullet, but I couldn't get the speed or accuracy IN MY RIFLE that I did with the Barnes. And, needless to say, that bullet is one deadly SOB. Good luck.

Gary

Flattened primers can also be a product of excess headspace. If the brass you were testing these loads in was previously unfired and a bit short to the shoulder, or full-length sized including pushing the shoulders back a bit too far, you can get mashed primers with normal pressures. What happens is that the cases will be pushed into the chamber by the firing pin strike; as pressures go up the primer will back out until it meets the bolt face; then the case body under increasing pressure will stretch back until the case head meets the bolt face, mashing the primer flat as it goes. Something else to check, anyway.

The only thing I can add is checking out your head space. Does the rifle have a long throat?

If so, then I sounds like you are seating your bullet either too deep or else touching the lands.

Some good advice above, but as an owner of about 5 6.5 x 55s, 3,000 fps is easily obtainable with a 125 grain partition, in a 22 inch barrel.

What brand of primers are you using also. Try the CCI Large Rifle. It is the hardest one. If you are still cratering that primer, I would go back to head space, or making sure of your throat length.

Good luck.

The 6,5x55 is pretty notorious for giving wildly varying velocities from rifle to rifle, but generally speaking, even in a "slow" rifle, you should see close to 2900 fps with the 125 gr, but don�t expect anything more. A 140gr bullet should see 2700fps and a 156gr bullet ca. 2550-2600fps.

As mentioned before in this tread:

quote:

---

I like R22 and R19

Ive used 4350 and 4831 , but got tighter groups with R22

Ive loaded 48 gr R22 with nosler 140 with good results , But I will back of alittle to 47 47.5 gr for longer case life

---

the slower powders are usually the best with bullets from 120gr and more, the latest "trick" here in scandinavia seems to be MRP2, that might sound slow but it works very well, giving good velocity and accuracy. 50gr MRP2 behind a 156gr bullet, another half-grain (or so, I have used 51gr but that is a hot load) with the 140gr bullets, these are max loads for modern rifles, of course. My experience is that Reloader 25 is very, very close to MRP2.

Another usefull powder is Vihtavouri N165.

And use Lapua cases, they are of excellent quality and not that expensive.

Least but not last check that you do not seat the bullets to close to the lands, it rarely benefits accuracy to seat the bullets close (and its usually impossible!)

Tron