270 WIN Reloading Question

That top picture is a definite sign of high pressure. I would say back your seating die off so it does not crimp. Make sure you weigh each charge on your RCBS 505 and just to make sure the 505 is weighing properly I would weigh some known weight. Even using the weight of a bullet will help check the scale. Make sure your primers are seated flush with the rim of the case. I don't like the idea that you are using Federal cases because in my experience they are notorious for having loose primer pockets. It may be that you have slightly long headspace and the firing pin is pushing the case forward, and the primer is backing out when the primer fires and the primer being slightly out of the primer pocket will cause it to look flattened. If you have a micrometer you could measure the diameter just in front of the web of an unfired case and then check it with the diameter of a fired case to see how much the case is expanding.

All of those primers look perfectly normal for .270 Win. I see an odd dark spot, but I assume that's camera shadow.

No ejector hole mark on the case head. No hard bolt lift. No high pressure. Imo.

https://www.thehighroad.org/index.php?media/albums/high-pressure-signs.148/

The 270 Win runs at 65,000 PSI. Any change in components (bullet) changes pressure . 61.3 grs is not for the Hormady bullet.

No better book. Sorry. I just watch for pressure signs and find an accurate load below listed maximums, when working up.

I alwas look at all bullet data , that use the 1 powder. A 135 or 140 gr bullet is of interest to me. Less powder. How much.

Note bullet construction. .
Lead core compared to all copper. Thick copper jacket, long bearing surface= more pressure.

Most iso-weight, iso-construction bullet swaps make little to no pressure difference, certainly less than chamber-to-chamber differences do. Work up, and you'll be fine.

After taking a 2nd look at the Winchester cases I don't think you are getting the primers seated to the bottom of the primer pocket and the primers don't seem to be seated straight into the primer pocket. The shape of the fired primer is out of round when it should look round. The rifle has at least .005 in headspace so the primer could be sticking out .005 or more and the bolt still close. Do you feel any resistance when you close the bolt on a loaded round?

You said you bumped the shoulder back due to being fired in your old rifle.

Maybe you had too much headspace when you bumped the shoulder back for the new rifle.

I would see if a fired round would still chamber. If so, fire another round with your last charge in that piece of brass and look to see if you still have a flat primer. Do not bump the shoulder back if it chambers.

No cratering and no flow.

Flattened primers don't always indicate high pressure. Just for kicks and giggles, load a few partially resized cases. Set your die to just touch the shoulder. It could be that you shoulders have been pushed back to far. That can cause flattened primers.

243winxb said:

No ejector hole mark on the case head. No hard bolt lift. No high pressure. Imo.

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I agree with 243winxb. I see no signs of excessive pressure.

Why are you crimping?

ditch the crimp.

your primer results are fine for a fully resized case.

start your c.o.l. (cartridge overall length) .020" off the lands (if the round will fit in the magazine).

let us know how it goes.

luck,

murf

I personally wouldn't be concerned, based on the pictures, due to the absence of extractor marks and cratering.

I don’t see high pressures.
I see the primers backing out due to excessive sizing pushing the shoulder back. Upon the firing pin striking the primer, the case is pushed foward. The primer upon ignition moves back to the bolt face. Under pressure of powder combustion, the case body stretches allowing the case head to re-contact the bolt face, reseating the primer making it appear to be excessive pressure.

Low pressure cartridges such as .30/30 and .35Rem will exhibit backed out primers, but cases won’t have stretched enough to reseat the primers.

Actually you’re seeing LOW pressure signs...

Primers should be seated 0.002-.003 BELOW flush...

murf said:

ditch the crimp.

your primer results are fine for a fully resized case.

start your c.o.l. (cartridge overall length) .020" off the lands (if the round will fit in the magazine).

let us know how it goes.

luck,

murf

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I agree with murf on this. Bullets against or into the riflings jump the pressure.

BTW: It'd be interesting also to try a different primer for reference.

Para1911A1 said:

Hello All,

I just got a Browning AB3 in 270 WIN. I have shot two boxes of Winchester Super X for the break-in procedures. I started to work up a load from min to max with 5 rounds in .2 gr. steps. I began shooting these test rounds but stopped at the third step because of flat primers (see Pics). I expected the primers to eventually show signs of pressure but not at min load. The flattening seems the same on all, but a little more than the Winchester factory rounds. I am very sure of the charge weights. From a RCBS measure then trickled up on an electronic scale, then verified on a RCBS 505 balance scale. I'm not having any extraction problems. Do these look alright? any thoughts? All the facts below.

CASES: Trrimmed Federal once fired.These were FL sized because they were fired in my old rifle.
PRIMERS: Winchester Large Rifle
POWDER: VihtaVoli N560 56.2 gr - 58.0 gr. (Max = 61.3)
BULLET: Hornady 130 gr, SST
CRIMP: Lee Factory Crimp Die
View attachment 855569 View attachment 855570

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Your reloaded cases look fine to me...No sticky extraction, no plunger ejector hole cut on base, no primer cratering...What is the pressure? Doesn't really matter because that load is safe in your gun. Without a pressure test setup your best bet is to look for the signs you have already identified and I would suggest a chronograph. They are cheap and as long as the velocities you are seeing are in the ball park of what the loading data indicates you are probably just fine. Ultra high pressures with normal rifle powders yeild excessivly high velocities so you will know if something is up with chrono data.

Para1911A1 said:

Agreed,
What's the best Chrono on a budget??

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I really don't know since I designed and built my own....But I use the CED M2 light sensor units with mine so I would guess that their full chrono setup would be a good one. The CED sensors have built in rate of change amplifiers so it was easy to make them work with my universal chronograph..

Para1911A1 said:

Ok Guys, I finally got a chrono and back out to the range. I fired some of the lower charge rounds over the chrono.

2913
2938
2928
2930
2950
2935
2959
These are the numbers I got. I understand that high pressure can be more accurately diagnosed this way. My new question is, at what fps would you be concerned enough to stop and pull the bullets?

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I read lots of material from the inprint crowd, from what they wrote, a 270 Win must push a 130 gr bullet 3000 fps or it is a failure. I wonder what mystical nonsense velocity criteria they would use if we were on the metric system. The number "3" really resonates with the Druidic types, and that is probably where the 3000 came from. I have pushed 130's to and above 3000 fps in 24 inch barrels and in every instant, I had pierced primers, blown primers, expanded case heads and sticking extraction. Fire enough fireballs and the truth will be revealed. I needed to keep 130's at or below 2900 fps, or I would always encounter a blown, pierced primers. It is not like bullets going 2850 fps are going to bounce off a mammal. Your barrel is probably 22 inches so I am going to say, your loads are smoking hot. I would cut them myself, but, if you are not experiencing blown, pierced primers, or expanded primer pockets, maybe your loads are OK. Just try them in 90 degree weather and see what happens. I have conducted a lot of load development in 70 F weather only to have problems when the temps got to be in the upper 80's.

I have forgotten who the author was, but I read an article on reloading when I first got into the game and the author opined that the single worst sentence ever penned concerning reloading was "Use the starting load listed in the manual you are using and work up to the listed maximum from there." He said, and I agree, be careful working up to any maximum. You should stop immediately when you see ANY sign of pressure regardless of how far away you are from the listed maximum. Then you should back off a couple of grains and consider THAT the load maximum in your gun.