I have worked up to 72 gr. Magpro (from 69 at half gr. increments), 140 gr. Nos Bal. tip seated .020 from lands,(270 WSM) new Win brass with WLRM primers. I only loaded and fired 2 rounds at 72 gr. On the first, the bolt felt a little sticky, but it drags some anyhow, on the second, no heavy bolt lift noticed. The primers seem slighty flattened but you really have to look to notice (this appeared and is the same as the 71 gr. loads). What I did notice is that the primers on the 72 gr. loads seem to have backed out a little, as the case wobbles when set on a flat surface. I checked some factory cases that I fired and the other reloads from 71.5 gr. on down and the 71 and 71.5 have a very slight wobble, but the 72 gr. load seems to have more. I have loaded 3 more rounds at 72 gr. but will wait to see some replys before I fire those. As a side note: the 2 rounds at 72 went in the same hole, the 5 at 71.5 gr. were scattered about a 2.5 in. group, 71 gr. had 2 holes touching with the others scattered and all others scattered and erratic.
Should I try another 72 gr. load?

I think it's your common sense trying to talk to you here, Felcher. When in doubt, back it off.



Is that last grain or half grain worth it?



At the very least you are probably sending your new cases to an early grave and potentially heading for worse problems further down the road.

Not necessarily. Could be caused by many different things like a soft primer.

I don't have a Nosler book with the 270WSM listing, but is 72 grains more than the max load?

What did your chrono show as you were going up in powder weight? If you didn't get about the same increase in speed from 71.5 to 72 grains as you did with the other half grain increases then you might have excess pressure.

I won't comment as to the pressure of your loads, but I do want to comment about the primers backing out. This is normally a sign of excess headspace, It could have been caused by the shoulders being set back while sizing the brass after firing. I was not sure if you said the factory loads did this as well, or only the handloads. Try backing out the sizing die a little before sizing (using new or factory brass), and the "primer rock" should disappear. Be sure that the die does not touch the shoulder to prevent future repeats of this problem.



As a further note, this condition could lead to case separations if you continue to use cases that are sized enough to let the primers back out, not fun .



There is one other situation that can cause "primer rock". That would be caused by the primer extruding back into the firing pin hole, but this is easy to tell from the primer backing out just by looking.



Jim

MagPro From 63.2 grains to 74.2 grains
Winchester LRM Primer

As for your "problem", there could be many causes...only you can decide, since you are the only one who can actively see and measure the cases.

I don't have access to a chrony yet, so I am unsure of velocity changes. As for headspace, I initially set the sizing die to allow the press handle to just barely cam over as contact was made with the shellholder. Once fired cases sized in this manner would not allow the bolt to close when rechambered in the rifle. I adjusted the size die down 1/4 turn (press handle cams over firmly as die contacts shellholder), and the cases now chamber fine. I am currently awaiting the arrival of my Stoney Point headspace gauges, so I will know more when they come in. The factory cases have a slight "primer rock" but not as much as the 72 gr. reloads.

If you cant rechamber a fired case then the load is probably too hot. You might have to punch the primers out if they are backing out of the case though. It might also help to know the brand of rifle.

A couple other things you might want to check are the dimensions at the base of the case on a new case vs. a fired case vs. a sized case. You can also remove the sizing button to see if the neck dimensions are too large. You should be able to see how far down the neck the die is sizing and if it is actually bumping the shoulder. Have you checked OAL?

Felcher you should try to chrono that load if you can . I have been working with a 270 WSM in a Savage rifle . I'm pretty sure the barrel is under size . It's going back to Savage (2nd time) for signs of exessive pressure . I had data from Barnes on the 140 TSX indicating 62gr. RL22 starting 66gr. max velocity 3066-3240 . The gun I was working with chronoed 3200 with 62gr . we bumped the load to 62.2 and it stuck the bolt bad enough to break the extractor. The gun exhibits very early pressure signs with all powder and bullet cominations including factory ammo.I load for several rifles and have been using a chrono , as suggested by John Barness , to watch for top "pressure tested" velocity to help determine where I'm at pressure wise . Some hit the top velocity early , ( not 4 grs. ) some can bumped over max it varies from rifle to rifle and lot to lot on powder for me. If you chrono the load and are much over published pressure tested velocity you probably are getting close on pressure. Good luck KHH

Thanks for all the input fellas,
The rifle is a Mod. 70 Supershadow
I have'nt tried to rechamber a fired case from these reloads, but a fired Win. 150 gr. factory will rechamber. I will try to rechamber one of the reload cases when I get home and will report. I will also make measurement comparisons of the cases. I will also readjust the sizer die (RCBS X-die) as CDH has suggested. I don't think the barrell is undersize as KHH had said he is experiencing, this rifle handled the factory Win. Supreme 150 gr. loads with no heavy bolt lift and no other pressure signs other than the slightly flattened primers. I know 1 guy in town that has a chrony and I will check with him to see if he could come check the 72 gr. loads for me, as I know nothing about setting one up and dang sure don't want to blow up somebody else's equipment. Thanks again for all the help, I will post again as I get more results.