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Old June 8, 1999, 12:31 PM   #1
Little-e
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I just started reloading for .223 and noticed the primers looked awfully flat after firing. None of them were raised out of the pocket and none had holes in them. Before loading, I trim every case and clean the primer pocket. Bullet is seated about .01" short of max. Load is middle of the road. According to the chrony, velocity is acceptable.

Do you think I'm missing something here or is this acceptable? The last thing I want is a blown up gun.
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Old June 8, 1999, 12:55 PM   #2
Mal H
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Flattened primers are not necessarily a sign of excessive pressure. If they still have some rounding at the edges, this is normal. If they are completely flat and fill the primer pocket, then you've got a problem. More reliable signs are: shells are hard to extract; you get shiny spots on the head from where the brass flows into the ejector hole (depends on the rifle). There are others, but these are usually always observed. More subtle are the louder noise and heavier than expected recoil, but these are usually ignored since you expect loud noise and recoil anyway. From your description, you're on safe ground.
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Old June 8, 1999, 01:27 PM   #3
Cheapo
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Other possible problems:

Cases are sized a bit on the short side, the fired in a chamber a bit on the long side. Initial pressure in the case sidewalls grips the sides of the chamber and the primer backs out a bit.

Then pressure builds more and the case either slips back a bit (okay IMO if it's only a small distance) or stretches back (bad if the distance is long). The backed-out primer then gets smashed into the outer corners of the primer pocket.

Run a patched rod down the bore to near the throat and fire a primed case (check, double-check, and re-check that it has no powder!). The distance the primer backs out can give you a clue.

The other potential cause that comes to mind is that the load was developed for a case with greater internal capacity than the ones you're using. This is not as much of a problem with .223/5.56 as it is in .308/7.62, but it *can* be a factor.

If your velocities are higher than advertised (or if you're shooting a shorter barrel than the load data used and are getting the same velocities), your load may not in fact be safe.

What primer are you using? Some "flow" more at top pressure than others...

Hope this helps.
Cheapo.
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Old June 8, 1999, 02:09 PM   #4
Mal H
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Cheapo - very good point on the velocity factor. I have had talks with some novice reloaders who say they can't get the velocity up to what it says it should be in the manuals so they keep adding powder (!) until it's close, thinking they are making safe rounds. They failed to notice that the tests were done with a 24" barrel and they have a 20" sporter! Always compare the test bbl to yours and take it into account when comparing velocities. So now, Little-e, with this in mind, is your velocity acceptable?
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Old June 9, 1999, 01:00 PM   #5
Little-e
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As for the first question, I'm using Winchester small rifle. BTW, the brass is once fired if I did not mention that before.

As for the second question, I'm shooting an AR-15 sporter. The velocity I'm getting is about 500 fps less than the test rifle which was a Rem. 700. I'm no mathimatician (sp?) but I'd hope that's close to correct.

Is there a publication that will break down velocities according to barrel length?
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Old June 9, 1999, 02:20 PM   #6
Mal H
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Little-e - 500 fps less than the exact same load out of a 24" bbl seems too low. Your crimp method may be too loose. If you use a crimping die such as the Lee Factory Crimp, it may help. You might actually have too low a pressure for the specific load.

As for how much less/more the vel. will be for a bbl of a certain length is very hard to predict because there are sooo many variables involved, temperature being one of the biggest. Lyman does have a table in their 47th manual that gives an approximate gain/loss for different length bbl's. They say you should see approx. 100 fps less in a 20" bbl compared to data for a 24" bbl using a 3000 fps load. I feel their data is conservative, and I believe they are assuming like rifle actions, i.e., bolt vs bolt.
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Old June 10, 1999, 10:03 AM   #7
Cheapo
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Next question, little-e:

Have you recently fired any Winchester ammo out of that rifle? *If* Winchester ammo of same bullet weight/construction uses Winchester primers (usually a "safe" *assumption*, with all cautions),

THEN

you can think about "reading" the primers for pressure signs.

I've seen USGI .30-06 Match ammo produce totally flat primers, with knife-edge corners, in Garand rifles. BUT those rifles had slightly long chambers (see my previous post re: primer backout), the load was indeed max, the weather was hot, and I suspect the primer cups were softer brass than usual.

Gotta compare apples to apples.

If your rifle is nevertheless attaining within 100 fps of what the factory ammo is getting with the same bullet weight and similar construction¤¤,
then I'd stop right there and call it good. Especially if the Win. factory stuff has primers less flat than your reloads OR you're above the factory load velocity!

Reloading manuals are fine, within their limits. Never be afraid to back off from a published load if it's behaving badly in your firearm.

BTW, action type is generally a factor only with revolvers. Semiauto rifles sometime give higher velocities with the gas port closed. Typical velocity loss, OTH, is usually only 25 fps.

¤¤
comparing 55-gr FMJBT with 55-gr thinjacket HPBT varmint-exploders is more like apples and oranges again--thinner jackets, different bearing surfaces etc.
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Old June 10, 1999, 11:53 AM   #8
Little-e
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I appreciate the info and will give the Winchester cartridges a test. Up until now I've been using Sierra and Hornady bullets and I'll let you know the results of the Win stuff. You guys are really impressive. Please see my post "Outstanding guys" under general.
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Old June 15, 1999, 11:43 PM   #9
Long Path
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One last suggestion-- Make dadgum sure that you're getting **all** the case lube off of your cases, and any other lube, as well, before firing.

The adherence of the brass walls to the chamber under pressure is extremely important, not only to your brass, but to the action of your rifle.

Sometimes, moderate loads with lube on the brass will allow the brass to slam backward instead of properly gripping the chamber wall with the expansion.
It seems to be just as common, if not more so, in the moderate loads, because the moderate loads do not get the full pressure up to expand the case walls, retarding the slamming into the bolt.


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