I'm loading for a 700 ADL 243. My components are Rem brass, Hornady 87 gr bullet, CCI 200 and 35 gr of IMR 4350. I loaded up a few rounds and they shot into 1" at 100. On all of them the primers backed out about .01 to .012. Might be the third loading of the brass, so not too old.

I've heard that primers backing out is sometimes the result of low pressure, but this recipe is towards the top of what my manuals show. Could my headspace be off, maybe back off the sizer a bit? Any other ideas?

I want to tweak my seating depth a bit as these loads were done to SAAMI length, but there is quite a bit of room to lengthen in this rifle. Don't want to tinker too much until I figure out why primers are backing out.

quote:

Don't want to tinker too much until I figure out why primers are backing out.

Primers always back out until they contact the bolt face. Normal pressure usually pushes the case head back over them and seats the primers flush with the case head.

If you're getting 10-12 thou of primer protrusion you're setting the shoulders back that much too far.

I just checked my Sierra manual and 37.6 is the starting load of IMR-4350 and a 90 grain bullet.
My sons .243 is really shooting tiny groups with 41.5 grains and a 90 grain Speer.
His rifle also likes 85 grain Sierra's and 43 grains of IMR-4350.
Your load seems on the very low end to me.

Went back and looked at my data again, must be low pressure related. I was trying to decide between 3031 and 4350, went with 4350, but used the weight of 35 gr listed with 3031. Not bad screwing up that direction, but could have been bad if I had gone the other way!

Will try 43 gr of 4350 to start with Hornady 87 gr bullet. Good reminder to keep your head on straight when reloading.

Low pressure loading. Primers will back out as they cannot swell and stay "seated"

Starting loads should be in the 37.5 grains range.

Here is a list at Steve's reloading pages.

I'm not sure I'd start as high as the 43 grains!

Graybird, if I'm reading the chart right, 43 is about in the middle for 87 gr bullets with imr 4350 or am I missing something? Looks like that chart goes up to 47 grains for that combo. Do you always start at the bottom? I don't do tons of loading, but usually start a little higher. I guess it seems like starting loads make safe loads for older weak actions, but maybe I should rethink my strategy.

Both Hornady and Nosler manuals say start at 39.5 (about) and stop at 43.5 (about).

I also seldom start at the bottom, but I'm not going to start .5 gr below max.

Primers don't " swell up and stay seated".
The primer pushes back against the breech
if you have headspace it will project.
If the pressure is high enough (30-40 k)
the case will come back over the primer.

Check your sizing die. Sounds like you are way over sizing your case.

You most significant problem is mis-reading the manual not the primers protruding.
Had you used the manual data correctly we would not have this thread. You were about one choice from a blown up rifle. BTW you could have blown up your rifle with a reduced load of 4350 too.

How are you going to correct this type of problem?

quote:

Originally posted by NMiller:
Went back and looked at my data again, must be low pressure related. I was trying to decide between 3031 and 4350, went with 4350, but used the weight of 35 gr listed with 3031. Not bad screwing up that direction, but could have been bad if I had gone the other way!

Will try 43 gr of 4350 to start with Hornady 87 gr bullet. Good reminder to keep your head on straight when reloading.

Yep; you have excessive headspace (you are probably sizing your brass too short); and that, combined with lower pressures, cause the primers to come out and the brass is not stretching or moving to cover them. Which is why you don't want excessive headspace. Read PO Ackley's tests on that subject and you will learn all about it. As you can see, the brass alone held all your axial chamber pressure, whatever it was, as none of it was transferred to the bolt face. Except for the primer, which is not much.

I usually do start at the beginning load, or very close to it. I load only a single round at those powder levels and work up 0.5 to 1.0 grain loads (dependent upon the cartridge) until I get to the area I'm interested in. In your case, it would be 43.0 grains. So, in this case, I would likely start at 38 grains loading a single round until I got to 43 grains, checking for pressure. Once at the 43.0 grains, I would back it off to 0.5 grains per powder charge change until I either hit pressure signs, or until I hit the max powder charge recomended.

Good luck,

I would measure my 1x fired brass and compare it to my FL resized brass. If you're going more than a few thousandths down on the shoulder you're over-sizing. You an use an RCBS precision mic or the Hornady/Sinclair system that clamps to your calipers.

Good advice guys. I will start at 40 and load singles to check pressures. On my once fired cases I should be able to neck size only as I only have the one rifle in that caliber, that should take care of any head space issues, correct?

I loaded some singles, the primers were flat (not backed out) when I hit 42 grains of 4350. No signs of pressure through 43, so loaded a few at 43.4, hope to get to the range today and see how they shoot.

quote:

Originally posted by NMiller:
I loaded some singles, the primers were flat (not backed out) when I hit 42 grains of 4350. No signs of pressure through 43, so loaded a few at 43.4, hope to get to the range today and see how they shoot.

Going past 43 gr may work with some components, but not all.

quote:

Originally posted by NMiller:
Good advice guys. I will start at 40 and load singles to check pressures. On my once fired cases I should be able to neck size only as I only have the one rifle in that caliber, that should take care of any head space issues, correct?

Possibly. Only if the once fired brass you have is expanding to the bolt face. Your brass you have been firing obviously did not do that. Maybe with more pressure it should but who knows. I would start out with some cases with proper headspace. Sizing your cases how you have been is dangerous and can lead to case head separations. If I were you I would slow down on the loading and read at least two basic reloading manuals so you get an understanding of the basics of die set up.

From other stuff I have read it seems like primers backing out is fairly common with low pressure loads. I could be having headspace problems, but I have set up quite a few dies and reloaded hundreds of rounds (not thousands like some of you guys) and haven't had issues like that yet. I think my problem with this was the low pressure which was a result of misusing load data. That is a real problem and something that will be corrected!

There were 5 rounds that failed to fire and 15 that did fire, then there is that part where the primer always backs out. I pulled the fail to fire down including removing the primer, all the weights and dimensions were weighed and measured, The rifle chamber was magnificent, the weights of the fail to fire were impressive, I installed the primers back in the same cases they were removed from, then, chambered them in one of my M1917s and fired all 5 primers, NO PRIMER PROTRUSION. or as they say, no backed out primers.

All the 5 fail to fire were chambered in 3 different rifles and at least 5 attempts to fire them were made. Anyhow, “the primer always backs out”? sounds good, there was nothing to drove the case head back to seat the primer on the M1917 because the powder and bullet were in medicine bottles, nothing but the primer and case. and still no back out, and we all know the M1917 has room between the case and chamber. I have one that requires a .014” adjustment to fit the case to the chamber.

F. Guffey