Backed Out Primers

[jj2am44]

Went to the range today to shoot some reloaded .308 rounds with 39.0 grains of Varget and noticed that most of the primers (Winchester)had backed out somewhat-maybe .5 mm. The bullet was a Hornady 168 grain BTHP in a Remington case. No problem chambering or extracting. Any ideas? Could the primer pockets have enlarged? Any way to check this? Thanks.

 

[4barrel]

Try a few factory rounds. I like Varget. Maybe a headspace problem. What kind of rifle? It is not the primer. Overloaded will be flat & flush.

 

[Rule3]

How many times has the brass been reloaded.

Has this ever happened before?

Ever use factory ammo and have this happen?

 

[scooter123]

I'll second 4 barrel's suggestion of a Headspace issue. Two indicators for excessive Headspace are primers that are "backed out" and excess case length growth at each firing cycle.

BTW, I don't like to see case growth of more than 0.003-0.005 inch at each firing cycle. Run your cases towards the "tight" side and you'll not only improve case life you may also gain a bit in accuracy.

Tip One. If you don't have a case gage for your Rifle calibers, get one for each caliber. They aren't that expensive and you can learn a lot by using them correctly.

Tip two. Test the Fit of your Fired cases in your case gage and use that Fit to guide you on setting up your full length sizing die for that specific rifle. If your fired cases sit high in the gage then set your sizing to run towards the "long" side. If your cases sit low in the gage then run your sizing operation towards the "short" side.

 

[hammer 1]

Hodgdon is showing a starting load for sierra 168 bthp with varget in 308 is 41 grs.

 

[jj2am44]

The rifle is a Remington 700 Police and today is the first time I noticed it. I have not tried factory ammo. I checked a fired round with a case gauge and the head end sits up above both steps of the gauge. The open end does not come up to the lower step. This will change after I resize, correct? I am not sure of the number of reloadings.

 

[jj2am44]

Hodgdon is showing a starting load for sierra 168 bthp with varget in 308 is 41 grs.

My Hornady book shows a starting load of Varget at 32.6 for a 168 grain BTHP.

 

[Geo. T.]

My Guess!

It could be head space but this often happens when pressure is low! You must be doing a good job of removing the oil from your chambers!

 

[505Gibbs]

It could be head space but this often happens when pressure is low! You must be doing a good job of removing the oil from your chambers!

Not the same animal but I've had primers back out on low pressure 22 Hornet rounds - FWIW.

 

[John R]

Bump the charge up a grain or two and your problems will go away.

 

[Rule3]

Hornady data is pretty anemic for the start loads of most calibers but it is tested and works. I have used the start loads in 223 and 308 (not with Varget though) Your load is low, but not that low, Hornadys max with THEIR bullet is 44.0 gr so you can try a little higher charge.

If you do not know how many times the brass has been reloaded than the pockets could be loose. Try some newer brass or better yet, invest in a box of factory ammo and see what happens before you go crazy on headspace issues of the rifle. Also check the length of the brass (not the loaded cartridge) after you resize them. Check your brass length with calipers, use the gauge to see if it fits correctly which would indicate how your sizing die is forming the shoulder of the brass, adjust the die if needed.

 

[jj2am44]

I do have a box of factory ammo I can try. I tried using my bullet comparator on the rounds in question and a factory round-they were basically the same measurement-1.620 inches-measured from the end of the brass to a point on the shoulder. Also, I ordered a gauge from Ballistic Tools to check the primer pocket. Basically, it is a go-no go gauge. Will report back. Thanks for all your help.

 

[Mad_Charlie]

Low pressure load.

 

[AveragEd]

Another "not the same animal" comparison but I've experienced the same thing with not just one but TWO Remington Model 700 Ultimate Muzzleloaders I was sent for testing. They utilize a shortened centerfire case and a large rifle magnum primer to ignite the black powder or substitute propellant and every "fired case" comes out of both rifles with the primers backed out almost one-third of the way. They are not cratered or flattened so they exhibit no visual signs of excessive pressure.

It happens with 90-grain (volumetric) to 200-grain loads and all propellants and bullet weights. Also, it doesn't matter if the cases are new out of the bag with Remington primers or ones I reprimed with Federal #215M primers. I think it indicates that these rifles are being manufactured with excessive headpace but Remington didn't seem to care too much about the condition.

To put this into perspective, the bolts of these rifles are identical to a normal Model 700 centerfire rifle's except the ejector plunger is omitted so the small cases aren't ejected and possibly lost (it's obviously a single-shot so rapid follow-up shots aren't possible anyway). The barrel's breech plug is shaped to bear against the inside of the primed case and it apparently fits against the base of the case tightly as shortened standard cases from a .308 WIN, for example, are said not to last long as they lack a relieved area around the primer's flash hole that the UML cases have. Given that, I would speculate that the fit is very tight.

I'm curious as the cause of your condition. Please keep us posted.

Ed

 

[Nevada Ed]

Hodgdon for a 308 165 shows ~42.0 to 46.0c max for Varget.

41.4grs is 90% of a max load and should be ok for a starting load. I have fudged a little below with several powders for xlite target loads.

the data for 32.6grs is at just 70% of the max loading and to my knowledge.................
only H4895 is the only powder Hodgdon list at that low of a reduced load in any of its data.

Ball powders usually do better a little above minimum loads for me, over the years. H380 and H414 may be an option if you want slow...........

good shooting.

 

[Rule3]

I agree Hornady loads are low compared to others. I had many discussions with 223 Rem and H 335. The Hornady data is lower than Hodgdon.

I did the whole ladder of Hornadys loads, they all work.

Hornady makes the bullet and tests the bullet, they do not print data in the manual that does not work,

Also for the OP how are you measuring or weighing your powder, are you sure it is calibrated and correct?? Stick powder get finicky in some powder measures,

 

[samnev]

Not the same animal but I've had primers back out on low pressure 22 Hornet rounds - FWIW.

I had the same problem with low pressure loads. But when that occurred the cases always has soot from the chamber not being properly sealed as a result of the low pressure.
I agree with the others have urged you to get a case length gauge. Your trimmed and sized cases should fall between the upper and lower levels on top of the gauge and even or very slightly below the bottom of the gauge if you've had to bump the shoulders back. I trim mine just at the lower level. Additionally you can check to see if you case heads are swelling by inserting a round backward into the bottom go the gauge. If they are OK the should insert almost to the shoulder of the case.

 

[jj2am44]

I agree Hornady loads are low compared to others. I had many discussions with 223 Rem and H 335. The Hornady data is lower than Hodgdon.

I did the whole ladder of Hornadys loads, they all work.

Hornady makes the bullet and tests the bullet, they do not print data in the manual that does not work,

Also for the OP how are you measuring or weighing your powder, are you sure it is calibrated and correct?? Stick powder get finicky in some powder measures,

I'm using an RCBS Chargemaster Combo scale/powder measure. What I am going to do is load 10 full length resized rounds and up the powder to 41 grains-the Hodgdon starting load -and see what happens. The measurements on new and the fired brass are so close that the low pressure has to be the cause. Now, when I say the primers are backing out- I mean maybe a half of a millimeter-not much. You can catch your fingernail on the primer.

 

[Rule3]

I'm using an RCBS Chargemaster Combo scale/powder measure. What I am going to do is load 10 full length resized rounds and up the powder to 41 grains-the Hodgdon starting load -and see what happens. The measurements on new and the fired brass are so close that the low pressure has to be the cause. Now, when I say the primers are backing out- I mean maybe a half of a millimeter-not much. You can catch your fingernail on the primer.

But you need to be sure the case is sized correctly and the shoulder of the case is correct. A Wilson case gauge is easy to use and worth it. You need to see if the case head is fitting properly,

Actually with some fired brass from YOUR gun you can just neck size them. Eventually they will need a full size,

 

[jj2am44]

UPDATE-
Cleaned and deprimed the brass. I used my bullet comparator to measure from the case head to the shoulder on the Hornady, the Remington, and I also checked a brand new Lapua case. The Lapua case measured 1.618 and fell below both shoulders of the Lyman case gauge. The Remington cases measured 1.618 to 1.622 and they were OK with the case gauge. I did find a few that were below 1.615 and I tossed them. The Hornady cases came in at 1.618 to 1.622 and were OK in the case gauge. Any Hornady under 1.617 failed the case gauge test. I will have to wait until I get the primer pocket go-no go gauge to check the pockets, but at this point, I would have to say that the 39.4 grains of Varget is a low charge and causing my problem.. I am going to load about 20 rounds with over 41 grains and see what it does. Thanks to all.