Problematic 22BR

[BradY]

Well im just about ready to give up on my 7 twist 22BR and 90gr bullets idea.

Whats happening is that I clean the barrel then shoot a couple of foulers. The cases from the foulers come back with some pretty full on pressure signs but once im into a string of shots the pressure signs back off a little. I did start at 30gr of varget and had primers with major extended strike marks and very hard bolt lift, now im back to 28gr and still showing some mild pressure signs like cratering primers. Cases are neck turned to give a .249 loaded round in the .252 neck chamber. Also im getting a ring around the base of each case when firing, its large enough to catch my fingernail each time i scrape down it. On paper its performing well for a few shots then out of the blue two or three shots will print a full 3 or so inches high, then go back to the same spot.

Im thinking along the following lines for problems.

1. My firing pin needs to be re-bushed. I havent had any trouble before with it though so why now...

2. Maybe the firing pin spring is toast and it needs replacing. Could be shallow striking the primers?

3. The chamber needs to be re cut to remove a burr.

4. I need to have the bedding re-done.

Can anyone offer any other opinions?

 

[LHSmith]

Whats happening is that I clean the barrel then shoot a couple of foulers. The cases from the foulers come back with some pretty full on pressure signs but once im into a string of shots the pressure signs back off a little. On paper its performing well for a few shots then out of the blue two or three shots will print a full 3 or so inches high, then go back to the same spot.

Are you using a good bore guide, one with an o-ring and swabbing the chamber after each cleaning? I suspect you may be getting the chamber a little wet with solvent.
On the vertical fliers, did you run through Speedy's checklist posted on the home page last week? Do you have a mirage shield on the barrel? Do you use a mirage board at the target?

 

[johnmyers]

Maybe try slower powder. I use H4350 in mine with 82gr Bergers and works great.

 

[BradY]

Well i have another variable that really could be the cause of my problems. One thing I forgot to do after necking the 6BR cases down was trim to length. With cases that were 1.573, I have a funny feeling that the case mouth was being crimped tighter onto the bullet and thats why I had pressure issues. Ive trimmed back to 1.545 and loaded three at 29.5gr of varget to see how they go.

I do have some 4350 but I did find the groups werent as tight with that powder. Just wish I had some more 90gr sierras to load in case it fixes my problems! I suppose it will give me a chance to have a real go with the bergers and also use up the box of JLK's I have too.

 

[NorCalMikie]

One of the first things you need to know is the "actual" chamber length. That way you'll know if you need to trim or not. I've got 2 different barrels and they measure 1.584 and 1.585. With the maximum case trim length at 1.560, I've got a long way to go before I need to think about trimming the brass.
Another thing to think about is that the 22BR will build pressure "real fast" compared to a 6 BR.
A .01 or .02 grain increase in powder charge will put you way over the limit. And you don't have to be "fast" to be accurate. Back off a bit on the powder charge and work your way back up. A bug hole is a bug hole no matter how fast the bullet is going.

 

[ThunderDownUnder]

Just wish I had some more 90gr sierras to load in case it fixes my problems!

Brad, I hope you meant Bergers and not the Sierra 90s you mention as quoted above. The Sierra 90gr MatchKings fly apart at velocities in excess of 2760fps. How do I know this? After reading horror stories of these bullets on this website I contacted Sierra and got it straight from one of their bulletsmiths.

Stick to the Berger 90gr VLDs or your problematic 22BR will become disastermatic!

Ian

 

[BradY]

Ian

Ive had no problems with the sierras at all. I have shot them with 31.6gr of 2209 just over 2900fps but that was when the smith took way too much throat out and they had 100 thou jump. Ive run out now, but still have maybe 40 bergers left to try again and also a couple of hundred JLK 90gr VLD's. Its a shame we cant get these here anymore as they are a really nice looking bullet!

I do have more sierras on the way so will let you know what they do. Rod Davies had trouble with them but I believe his throat was pretty rough. He did say the bergers were the pick of the two in regards to holding together but sierras shot better for him.

Time will only tell I guess!

 

[ThunderDownUnder]

Brad,

This is the response I got from Duane Siercks (Sierra Bulletsmith) in regard to the 90gr MKs velocity limit without blowing up! I also asked if pointing the bullets might help by closing up the meplats.

I quote...

"We developed the bullet for the 223 with a max velocity of around 2650 fps. We recommend not exceeding that velocity by much. Pointing might help, but we have not tested that as yet. Thanks"

Hope this helps!

Ian

 

[BradY]

Well I went out and fired off 3 rounds with 29.5gr of varget (2208) and im still getting a ring around the base. Primers had a slight crater, but trimming them seems to have eased pressures greatly. Im of the opinion the primer strike is quite shallow and will get the pin bushed and the spring checked by my gunsmith and we will look at the chamber and see if there is a burr. Does anyone else have an opinion? Im thinking of getting the barrel bore diameter checked in case its a tight barrel as well.

After that im out of ideas...

 

[BradY]

Here is a couple of pics

 

[ThunderDownUnder]

Those pictures really show a problem that is difficult to understand. Your load is pretty safe at 29.5 grains of Varget (AR2208) but its showing head separation issues. Have you tried the bent wire down the neck to see if you can feel the ridge line inside the case?

Can you post the reamer diagram or did your gunsmith provide it? I'm using a grain more than you are in a Barnard Model P action with a 31.5" Krieger, 7 twist barrel and a no neck turn chamber (0.254") with only a bit of (CCI 400) primer cratering. The cases come out of the chamber without any real pressure signs at all and with easy bolt lift. My chamber has a 0.078" freebore specifically for the use of the 90gr Berger VLD bullet, any idea what your chamber is using for this dimension?

Are you using magnum primers? maybe hot primers could account for pressure problems?

Your inconsistent groups could be attributed to the VLDs not being jammed enough into the lands, read the info on the Berger Bullet website about seating depth with the VLD bullets. Try jamming them 0.030" into the lands with your 29.5gr load of Varget. I bet this would tighten up your groups considerably.

Ian

 

[BradY]

I just pulled the barrel out and there is a mark right at the edge of the chamber. Im wondering what could have done it- possibly a piece of metal at the end of the reamer that didnt clear out properly. Taking it in tomorrow to fix it. I did try the bent piece of wire trick and the cases are fine. It looks to be a little low for a case head separation. Lets fix the burr, I reckon thats it, and getting the firing pin bushed would be clever too.

My chamber is a slight turn .252, and yes using CCI 450 primers. If I didnt have magnum primers, I dont know what would have happened over the last few days.

Ian what length do you trim your cases to? The other 22 BR shooter here (I used his reamer) goes to 1.520 but i was thinking thats a tad short. Ive gone to 1.545. Getting another box of brass the weekend coming so this week I can focus on getting the chamber and firing pin etc done right.

 

[ThunderDownUnder]

Brad, trim cases to 1.545" sounds good to me as my reamer diagram indicates that its cut for a 1.555" case length. Its good news about the burr in the chamber causing the mark on your cases.

I'd lose the CCI 450 primers and go with CCI 400 or CCI BR4 (thicker cups). You want a full case of powder and using the hot primers means using less powder in the case to avoid pressure problems.

It seems with your chamber cleaned up and CCI 400 primers being used with your VLD bullets jammed 0.020-0.030" you will be drilling the centre of your targets with every shot.

Good luck Brad, I think your problems will soon be left behind!

Ian

 

[BradY]

Thanks mate. I have used the CCI400's in my 20 practical but found the cups were pretty weak- I have a box of federal 205m's that might be a better choice in the BR but I will work up some loads and go from there. I will get back out for another crack at tomorrow afternoon with the left over pieces of brass I have. Will go and do up some for a ladder test with the 90gr JLK's and bergers now.

 

[SpencerC]

The 450's and BR4's have the thick cups, the 400's do not. In my .223 using the 90VLD's, I have had better success jumping them .020 than jamming .010". I should try a .020 jam and a .040" jump and see what happens.

 

[Alycidon]

In my book those primer craters show some severe pressure issues. If it was mine I would be looking to drop at least 2 grains of powder.

A

 

[rogn]

May just be subjective, but necks look long in the picture. Once had 2 necks wind up a tad long after initial firing(dumb a$% didnt measure 'em). Popped a primer on the first one and found the second on measuring....

 

[sharps]

PUT A 14 TWIST BARREL ON IT AND QUIT THE FOOLISHNESS,IF YOU WANT TO SHOOT A 90 GR.BULLET BUY A SPARE 243 BBL AND YOU WONT BE WASTING GOOD LAPUA BRASS TRYING TO DO WHAT A OFF THE RACK FACTORY CHAMBERING WILL DO WITH ZERO PROBLEMS.....TRYING TO
MAKE A BOWLING BALL FLOAT IS NOT IMPOSSIBLE BUT WHAT
YOU ACCOMPLISH IS IS SO USELESS YOU JUST WASTE GOOD
ENERGY FOR CREATING SELF INDUCED HEADACHES....

 

[ThunderDownUnder]

PUT A 14 TWIST BARREL ON IT AND QUIT THE FOOLISHNESS,IF YOU WANT TO SHOOT A 90 GR.BULLET BUY A SPARE 243 BBL AND YOU WONT BE WASTING GOOD LAPUA BRASS TRYING TO DO WHAT A OFF THE RACK FACTORY CHAMBERING WILL DO WITH ZERO PROBLEMS.....TRYING TO
MAKE A BOWLING BALL FLOAT IS NOT IMPOSSIBLE BUT WHAT
YOU ACCOMPLISH IS IS SO USELESS YOU JUST WASTE GOOD
ENERGY FOR CREATING SELF INDUCED HEADACHES....

No talk of floating bowling bowls here!

This has been done successfully many times, I know because I have one and it shoots unbelievably well and here's an article on this website for disbelievers like yourself. http://www.6mmbr.com/T2K22BR.html

Some people see only problems while others find the solutions that work and work well!

Ian

 

[AckleymanII]

What ever you do, don't use the Fed 205, the cups are very thin. Rem 7 1/2, CCI BR-4, and the CCI 450's have thick cups.

Your primers are not cratered bad at all, probably an issue of over size firing pin hole in the bolt. This is especially true if you are not having any problems with the brass needing full lengh sizing or the shoulders bumped back.

?The primer issue may have you backed off on your powder charge where you can't get to the accuracy node.

Good luck!