20 Practical fireform..UGH!

[Cakes]

Had the itch to build a 20P so got a x-caliber 11 twist, 3 groove along with new bolt and "cannibalized" one of my 6 AR/T40's. Went together quite nicely and initial results with N-133 and Speer 39 TNT's and 39 Sierra BK's looked good. Had ordered 2 (100 count) bags of new WW 223 Rem brass from a major vendor and when I primed them with BR-2's I noticed the tension to seat was lighter than normal (don't have a force gauge on my AR priming tool). Fire-form load was 24.3 of N133, 10 thou off and loaded NKD of .228. They did group fairly well with no pressure signs noted. Tried to do another test with fireformed brass and 50% of the primer pockets won't hold a BR-2 and even tried some Tula SRM's which run a bit larger and they're all very loose as well. Pulled out some Lapua brown box .223 and prepped them and priming tension was normal but with the thick necks these loaded rounds are .231 which will work now in winter but probably a no-go in the summer with the .233 chamber. I'd rather not turn necks on this project. Long rant...bad brass or too hot of fireform load? I've read where LC is a go-to brass but didn't expect to find these problems in WW after one firing. This is a AR yote/p-dog set-up. Comments/suggestions please. Eric in DL

 

[Wirelessguy2005]

could be a number of things but i think i would look at the primer pockets in that ww brass as the primary problem. The last batch of ww brass i worked with was 204 and it had a number of problems. I have found that the quality control on ww brass has went down significantly over the last 10 years. If you have access to LC brass you might give that a try, IMI is also a great option if you can find any. I am not that familiar with V-133 but i can tell you that Ramshot Xterminator and H4198 are both great powder options in the 20 prac and or the 20 tac.

 

[Ksmirk]

My little brother just went thru this but with 243 WW he was sizing up to 260, he bought some go/not go primer pocket gages and has been sorting and finding several that the pockets are large. I think he's saving them and I've tried to talk him into contacting WW and let them know but this has been a problem for a bit from what I've read.

Friend of mine just finished a 20P but he used LC brass and haven't spoke with him about his experience with it this past weekend but I hear it's a nifty little round but I'm a 17 Rem guy good luck and I'm putting my money on the brass is not to spec with the primer pockets. Later,

Kirk

 

[223Randy]

Are we talking 20 Practical or 20 Tactical (Practical doesn't get fire formed?)

 

[Charles]

Just did a 20 practical with a x caliber barrel using LC brass on my 4th loading of 20 dedicated pieces of brass pockets not as tight as first round but nothing wrong with them will shoot them till a problem comes up. Got the barrel from a forum member and it shoots in the 2's at 100 yds. it is a joy to shoot.

 

[jepp2]

They did group fairly well with no pressure signs noted.

What I hear: neck tension seemed weak, OAL puts bullet 0.010" off lands, 50% of primer pockets oversize after first firing on WW brass, fired in an AR.

What my experience says: Did you check to make sure the chambering action wasn't seating the bullet into the lands? I ran your load through QL without knowing OAL or WC of your cases. QL predicts peak pressure of 63K which is 8K over the max. Where did you get your load data from and I assume you decided not to do a load work up to your max load?

I use WW brass in 20 Bobcat and 204 Ruger and have had NO loosening of primer pockets. I just haven't used any in my 20 Practical.

I process a lot of once fired military 5.56 brass. I run into loose primer pockets depending on the conditions it was fired under. If it was a hot day, primer pockets will loosen up. But I will see ejector marks before primer pockets become loose. If the pockets are loose, the ejector marks will be significant.

I'm not sure why you felt fireforming was necessary. When I form 20 Practical brass, it is the same as when I resize fired 20 Practical brass. And I have to assume you meant CCI BR4 primers, because if the pockets were loose with BR2 primers (large rifle), you do have some serious pressure problems.

 

[Cakes]

jepp2-
glad you caught that "senior moment" with the BR-2/4's. I classify all brass that has not been formed in that chamber as "not fire-formed" if you follow my train of thought. Even thou both have the same parent shoulder angle, the brass has not been "fire-formed" to that particular chamber reamer. As there isn't a lot of 20P load data I picked a handful of powders and mid values for powder charges. i just listed one of the 6 different loads that I started with..all experienced loose primer pockets with no ejector marks or even the slightest flattening of primers. Loads @ 10 thou. off are at 10 thou off with my tools and procedures. OAT was a cool 25-35F. for all range sessions and velocities where not over the top at 3500-3650' for the various powders and 39 grain bullets. I'm thinking if I "pinned" these new primer pockets I'll find them slightly oversize. I do appreciate the comments and just might have to neck turn some of my Lapua 223 brass to solve this issue. Anybody know the neck thicknesses on LC brass? Thanks, Eric in DL

 

[jepp2]

Anybody know the neck thicknesses on LC brass?

On my LC 20 Practical brass loaded necks run .2273 - .2278". I could give you the actual neck diameters after sizing down, but there is a lot of variation in the neck thickness. So I just go with the loaded neck OD.

Hodgdon Load Data has loads for 20 Tactical for 32 and 36 gr bullets with Hodgdon powders. It is very close to the 20 Practical on case volume. I could share a summary of my 20 Practical loads, but I use 32 grain bullets in it, and it looks like you prefer the heavier bullets. I tend to use those in my 204 Ruger.

 

[LitLBoy]

8208 is a great powder for the 20P and the only brass better than the LC might be Lapua, but it isn't necessary. Something close to 27gr. of 8208

 

[hogpatrol]

TOO MUCH POWDER!!! Thats a very hot load in an AR and even a bolt gun. I use 24.0 of N133 and Remington brass with 32s and 23.1 with 39s. Never had an issue with primer pockets and I've used 7 1/2s, BR4s, 400s, 6 1/2s, Fed 205s and 205 match primers with quite a few different brands of bullets. Too thick necks and subsequently larger loaded necks precludes me from using Lapua and some other brass brands.
On my bolt gun in the same caliber, I get hard bolt lift with 24.7 of N133 and 32 Vmaxes. Having said all that, I say your loads are way too hot.

 

[Cakes]

I appreciate all the info. The primer pockets on this new WW brass is larger in dia. than once fired FC and brown box and blue box lapua. BR4's seat with very light tension and Tula SRM's seat light but acceptable in the new brass. All are too loose in once fired, probably due to my "hot" loads. I'll back the loads down and try again with some LC or another lot of WW. Many thanks, Eric in DL

 

[pete1955]

Lake City 5.56 and commercial contract 5.56 cases are made of harder brass. Also the flash hole web is thicker that adds radial strength to the base of the case. I have brand new factory loaded Federal .223 cases that had over sized primer pockets after the first firing.

QUESTION, do you have ejector marks on the base of your cases. Meaning did the brass flow into the ejector.

Below a comparison of the flash hole web thickness and why Lake City brass holds up better for reloading.

Simple Trick for Monitoring Pressure of Your Rifle Reloads
http://www.hodgdonreloading.com/rel...-trick-monitoring-pressure-your-rifle-reloads

 

[Cakes]

pete1955-
Nice pic, I have seen it before and was aware of the thicker web on the LC/military brass. Answer to your question is; no ejector marks at all, primers not flattened one bit and still had a nice radius on the edges. Velocities were not extreme but I'm guessing the stout loads along with very cool temps and slightly oversize primer pockets to start led to this issue. Eric in DL

 

[jepp2]

Below a comparison of the flash hole web thickness and why Lake City brass holds up better for reloading.

I have seen that exact same picture numerous times. Did you section the cases or, is this just information you came across?

My reason for asking is I don't doubt the picture. Everyone can see the difference in web thickness between the two cases. My problem comes in that I have never been able to actually find any brass that the web varies even close to this much. Two operations I perform: uniforming flash holes and swaging primer pockets both would be SUBSTANTIALLY impacted with even half that much difference in web thickness. And I am talking running 10's of thousands through equipment. So I'm just trying to understand why I have never encountered this.

But I have to confess I haven't actually sectioned cases, but I could easily measure webs on a multitude of different cases to see the actual difference. Just trying to better understand this.

 

[pete1955]

Jepp2

The image came from AR15.com and you do not need to section any cases. Google .223 brass thickness and then click on images.
https://www.google.com/search?q=.22...hVD62MKHcjtBO8Q_AUIBygC#imgrc=b6KNNyzHwkwNHM:

You will see photos of a 2 inch rod and vernier calipers used to measure web thickness as a comparator.
All you need to do is drill into one end of the rod to hollow it out so it fits over any burs on the inside of the flash hole.

I prepped hundreds of these Federal cases, sized, uniformed primer pockets, uniformed the flash holes, etc. And then found out many of these cases had over sized primer pockets. All these Federal cases were from 2005 and Federal later fixed the problem. "BUT" Federal was then known for "soft brass" and had a bad reputation.

I have pin gauges and check all my primer pockets with a pin gauge .0005 smaller than the primers I'm using.

If any primer feels loose when seating I use a Lee deprimer tool, and if it moves with just finger pressure the case goes in the scrap brass bucket.

Read the postings by dryflash3 the moderator where all this came from.

https://www.ar15.com/forums/t_6_42/343739_.html&page=1

 

[pete1955]

As a side note this is done on AR15 rifles, these rifles are over gassed and can pop out the primer and it ends up in the trigger group.
And loose primer pockets can also erode the bolt face from leaking primer pockets.

The photo below is also from AR15.com and the poster said he didn't worry about loose primer pockets. And he would just change the bolt when it got bad enough.

I reload for my sons AR15 and dad isn't going to be blamed for stupidity and a etched bolt face.

.223/5.56 - Cleaned, Deprimed & Swaged - LC Only - 200 Pieces $28.00 free shipping
http://brassbombers.com/223-556-Cleaned-Deprimed-Swaged-LC-Only-200-Pieces-5LC-SSP20.htm

 

[P72]

I have been loading for .20P for 3 years and have established a max load of 25.5 8208 with 40 VMax bullets. I use either once fired RWS or Remington brass with some PMC brass (cheap). No high pressure issues like blown primers or enlarged primer pockets. As you would expect even tiny powder charge increments can make for big pressure variations in the tiny .223 case. The Hodgdon manual has some 27 grains of 8208 for .204R loads with 40 grain bullets and the .204R is somewhat bigger than the .20P.

After necking down from .22 to .20 I would logically expect some variations in neck wall thickness so I turn necks on brass that has been passed over a .20 expander after being necked down. Setting the cutter blade (tool steel periodically sharpened with a diamond hone) so it barely touches the surface on the neck of the case I turn the necks using slow as possible speed with my cordless. Just skimming the surface of the neck reveals substantial variations of neck thickness of .001-.002 inches; observing that variation provides justification for performing that simple and speedy task.

To Pete1955 - thanks for the photo - I will probably now use a hacksaw on my .223 brass to examine the inner dimensions. I would do this as the inner dimensions would probably change year after year, lot to lot. No big deal - a 22 tooth / inch hacksaw would probably slice through the relatively soft brass almost as fast as I could "google" an image, measured by others and probably not applicable to my brass.

Sounds like too much gun powder but a batch of bad brass might cause this and if bad brass is suspected the primer pockets would need to be measured before loading and then firing them off. I never had loose primers occur on new brass but I guess there always could be a first time.

I never heard the term "over gassed" in respect to type of gun in this case an AR. Looks like too hot a load on that case also. Possibly the owner might consider gluing in primers for subsequent loads if the brass is not tossed (not serious just joking - but showing the same attitude to the problem as replacing the bolt part).