I think I got hosed.

[436]

all,
So I have a .22-250 model 12 fv savage that we were trying to come up with a load for to go p-dog hunting. After trying 4 different kinds of brass, 6 different bullets, 2 different primers, and having all of them blow out and flatten primers I concluded that something was wrong with the gun. Took it to a custom rifle maker/gun smith, he checked it with go/no go gauge and said the head space was too long. However he did not have the savage barrel nut wrench, so he could not complete the job by fixing it. So I took the gun to another gunsmith who assured me that the headspace might be correct and that there could be other overlooked problems that were causing the blowing out and flatning of primers. Went to pick the gun up today and he said that he used a bore scope and found an excessive amount of copper in the rifleing so he cleaned it very thouroughly. I could see where excesive copper would create extra pressure. But what I don't understand is where it came from. When I clean the barrel, I do a very thorough job, and I use sweets which is known to be a very strong solvent. The cleaning method that I prescribe to consists as follows...
1. Hoppes no 9 powder solvent on wire brush, 30 strokes(to break up powder and carbon residue that lies on top of copper)
2. Dry patches until they appear as clean as they were when I put them in.
3. Hoppes no 9 powder solvent on wire brush, 30 strokes, this time I let it soak for 30 minutes.
4. Repeat step 2
5. Hold gun up stock down barrel pointing straight up. Use old pistol cleaning rod with big cotton swab on end to jam into back end of barrel through reciever. Next poor sweets down inside of barrel and let soak for 30 minutes.
6. Repeat step 2.
7. Repeat step 3.
8. Repeat step 2.
9. Repeat step 5.
10. Repeat step 2.
11. Keep doing this until copper is no longer visible.
I last cleaned the barrel probably 100 shots before he saw it, is it possible that the gun built up that much copper in 100 shots? I have never heard of this...

Prairie,
Just some off the wall thoughts and questions on my part. Could it be that your chamber neck area is a little tight. Is your bullet touching the lanes and grooves? To me it sounds like in the end it's going to be {as stated} combination(s) of small things that's causing the pressure, not just one obvious thing.
As for the barrel cleaning... I'm a big fan of a patch and Kroil oil... and once in great awhile a little J.B's fine bore paste.
Pressure problems and scale problems always go hand and hand, especial when you're using a powder and charge weight that has some real poop in it.
Personally my last primer problem was associated with a firing pin that needed to be bushed.
I know allot of these points have been made one way or another... but I thought I'd add mine...
Good luck.
436

 

[bigngreen]

I took some brass to the gun smith from several handloads after he had "cleaned the gun properly", (savage model 12 fv) and even though they showed several spots where the bolt face had imprinted itself on the base of the case, and even though several of them had flattened and cratered primers he said that they looked fine. So after hearing this I worked up several loads for a ladder test today. The first shot at the minimum charge, as stated in the speer reloading manual, blew the primer out of the pocket and stuck the case inside the chamber. BTW the load was 55 grain v-max, winchester brass, cci no 200 large rifle primer, and a min charge of 32 grains of varget. The one and only shot that I got to take chrony-ed at 3806. Took the same load with a different oal for my mauser action based .22-250, and was able to shoot the whole ladder test without any problems. The first charge on the mauser was chrony-ed at 3351. The gun smith that used the head space gauge and that diagnosed the savage as having too long of a headspace did not have a savage barrel nut wrench, so he recommened that we take it to Shillen, in Ennis Tx.

I'm not quite clear, did you shoot the Mauser length ammo in the Savage fine or just shot the same load with different oal in the Mauser?
If I had the cases I could show you some that came out of a 270 WSM with long head spacing that I bet look just like what you have. The cases would slam back so hard that the brass would go into the ejector hole and the primers came out so far that when the case slammed back it flatted them to the point that they were smooth across the edges and the center had a huge crater. They wouldn't hold a primer again either, that was 66gr of Retumbo after correcting the head spacing I shoot 71gr with no issues! It shot factory loads just fine also and loads seated near the lands.
I've ladder tested 32 to 36gr of Varget in a Savage model 12 22-250 with the 60gr Berger with no issues.

 

[loosesniper2000]

I had a 1000yd rifle do this to me and it was very frustrating after all the case prep. The gun started to do this after 1500 rounds through a Hart barrel. I took it to a well known smith and found out the first 3 inches had the "alligator" look to it which resulted in increased pressure due to the fact that gas was leaking and therefore increased the c.u.p quite considerable. The fix was simple, he just cut off a few inches and rechambered it. It worked fine after that.
Now, before anybody questions the above solution, I really don't know the specifics but I know the gunsmith did

 

[SBruce]

There's alot of ideas here on what the problem is, so I won't speculate on that. One thing I can say for sure though is that your real pressures have to be pretty high. In my experience, it usually takes a hot load to get 3800'/sec or faster with a 55 grain bullet. Usually, book maximum or close to it. Did you chronograph any of the factory ammo in it??

One 22-250 I have only gives 3750'/sec with 36.5 varget and same primer, brass and bullet you mention, that's with a 26" barrel.

If everything checks out (headspace, chamber neck, scale calibration, brass, ect..............perhaps you just have a tight bore. Which isn't necessarily a bad thing if it will shoot good and the bullets hold up.........less powder to get the same velocity.

You can do a makeshift headspace measurement with a RCBS Precision Mic. It cost about $50 if I remember correctly and it measures off a fireformed case. You can also get a chamber neck length gauge from Sinclair Intl. They don't cost much either. RCBS makes a certified scale check weight set. You can check all those things without going to a gunsmith. You can also do a chamber casting without going to a gunsmith (so I've been told, never actually done it).

Hope you get it figured out, but if all checks out ok, maybe just try shooting less powder, aim for around 3600-3700 '/sec and see how the primers look then.

 

[Fitch]

The problem is definitely not there with factory ammo, I have shot winchester, and hornady factory ammo and the primers appear just fine.

You just answered your own question. Your reloaded ammo is causing the problem.

As far as my cleaning method, and waiting till 100 rounds to do it; guys, this is a prairie dog rig, and for personal preferances, I don't want to stop after every 20 shots to clean the gun.

Your cleaning method is seriously flawed. Hoppes #9 sucks for removing copper. Period. I haven't used #9 in years.

Use SLIP2000, GM-TEC, or some other proven carbon remover first to expose the copper. Then use BoreTech Eliminator, Sweets, 50BMG, WipeOut, or some other proven copper remover.

This is the best article on cleaning I've seen in a long time: Bore Cleaning Method

You can remove a bunch of carbon and copper in a few minutes with the right chemicals.

That said, IMO cleaning is not your problem. Your reloaded ammo is the problem.

I know it will make for better accuracy, and the barrel will last longer...but when I'm prairie dog hunting I want to shoot accurate, dependable hand loads, for a whole weekend.

That's a good goal - but it doesn't mean you can't clean. To meet your goal: First, develop some accurate dependable handloads that don't flatten primers. Second, use the right chemicals, and the right process, and you can at least clean every evening and start the next day with a clean bore.

Fitch

 

[rscott5028]

Get the Hornady bullet comparator and headspace attachment sets for your calipers and measure every aspect of the fired and unfired factory ammo that works fine vs the handloads that are not working.

- case length
- headspace length to the datum line
- COAL to the ogive
- neck wall thickness

If you're right on the cusp and the neck pinches the bullet, there's a fine line between normal and very high pressures.

Neck size one of the factory cases that fired ok and shoot a starter load. Be sure to check the length in case it's stretched. (Compare it to SAAMI and also to the actual cases that fired ok.)

-- richard

 

[Prairie Dog50]

Well boys,
I was wrong, took the gun to Shilen, and had them check it out. I got to watch them use the Go-No-Go gauge, and the head space is 100% with-in tolerance. Next they used a bore scope, and showed me all of the excessive copper build-up, and said it was way more than what was possible with the only 18 shots that I had fired through since the last cleaning done by a quote-un-quote gunsmith. They showed me the proper way to clean it, and sent me on my way. We have one other gun that has probably received slightly more abuse than this one, and it has yet to show any signs of excessive pressure, and drives tacks like nobodies business, I guess we just got one with a temper this time. By the way the one that drives tacks like nobodies business is a custom .22-250, built on a mauser-yugo 48 action, with a heavy countour Adams and Bennet Barrel. The gun is outfitted with a timmeny trigger, and a tasco varmit scope. We have killed numerous prairie dogs with this gun at ranges over 500 yards. It looks like a turd, but shoots like a dream.

 

[bigngreen]

Wow, that's a lot of copper. Was it building up in a certain area or the whole length?

 

[Prairie Dog50]

Wow, that's a lot of copper. Was it building up in a certain area or the whole length?

There was an excessive amount covering the whole length, but there was a noticeble amount more around the chamber throat area.

 

[rscott5028]

I guess it's a good thing the first "gunsmith" didn't have a Savage barrel nut wrench.

What bullets are you shooting?

Would moly coated be better or worse for a high volume varmint rifle?

I wonder if lapping or Tubbs Final Finish would help alleviate that problem?

-- richard

 

[Prairie Dog50]

I guess it's a good thing the first "gunsmith" didn't have a Savage barrel nut wrench.

What bullets are you shooting?

Would moly coated be better or worse for a high volume varmint rifle?

I wonder if lapping or Tubbs Final Finish would help alleviate that problem?

-- richard

Hornady V-Max's, and yes moly probably would be better, but they're more expensive, which to me personally negates high volume. As far as lapping or using the Tubbs Final Finish, it might help but I hate to take that kind of chance and ruin the guns accuracy. We've shot multiple sub half moa groups with a variety of loads.

 

[rscott5028]

Hornady V-Max's, and yes moly probably would be better, but they're more expensive, which to me personally negates high volume. As far as lapping or using the Tubbs Final Finish, it might help but I hate to take that kind of chance and ruin the guns accuracy. We've shot multiple sub half moa groups with a variety of loads.

I sure don't have the answer. But, I'm just curious why that rifle seems to build up copper more so than your others.

- bullets
- throating
- bore dia
- bore finish

There should be a way to mitigate the effects and maintain your accuracy so that you're not spending all your time cleaning while your buddies are whacking pdogs.

-- richard

 

[ken snyder]

I've seen unusual copper build-up when using bullets with different jacket materials, I'm not sure but I think the harder residue promotes excess stripping off of the softer jacket. An interesting foot note about moly (my friends and I don't use it anymore) We found that cleaning them always resulted in higher pressures because the moly was no longer coating the barrel. even with various methods of ironing in it still took quite a few rounds before they behaved properly.

 

[mtang45]

Well boys,
.... all of the excessive copper build-up, and said it was way more than what was possible with the only 18 shots that I had fired through since the last cleaning done by a quote-un-quote gunsmith. They showed me the proper way to clean it, and sent me on my way.

I have read this whole thread and I'm still confused. If the high pressure was caused by copper build up, then why did the factory ammo shoot just fine?

I'm wondering if perhaps what was perceived to be copper build up was actually brass from case necks being too long, and small shavings were pinched off by the projectile as it entered the bore. Under the heat from the friction/high pressure gases the brass shaving could be "melting" into the lands and grooves as it travels down the barrel. Copper and brass would certainly look the same through a scope if the brass was deposited in this manner.

Just speculating.