.17 WSM Pressure signs in B-Mag

Greetings. I am wondering if any of you are observing any signs of over pressure in your .17 WSM's when fired from the B-mag rifle? I have only fired about 41 rds thru mine so far but have found two cases which split at the neck or near the shoulder of the case. I am not seeing any evidence of then having been annealed like is commonly done with .223 cases and other high pressure bottle neck cases. Being cheap, rimfire, throw-away cases, maybe this is OK? but it was new to me and I thought I would post it here to see if it is common or unique to my gun and ammo lot?

In both cases it was when firing the 25g ammo. I have not yet had the chance to try the 20g ammo. I can imagine that a loose chamber could also cause this but... I am a reloader with many years of loading experience. I have seen similar case failures in both .223 and 45 ACP cases when both loaded to near max and when reloaded many times. After a while they just become brittle and/or wear out. Never saw such failure on once fired brass.

Irish

Hi. I've only got about 30 rounds (25 gr) through my rifle, but will watch this for sure!
BTW, Winchester said they could go higher in pressure but decided to stay on the 'safe' side. This was in either Shooting Times or American Rifleman......Also hinted about a 22 and 25 cal SM.....
The wheel keeps getting reinvented... ha ha

ron

I have shot 51 rds so far and have not had this happen anymore. Just the two cases. Could be a fluke or my chamber is a little loose, or the brass is just brittle. I dunno. I have not put any across the chrono yet but others have reported that they are a little faster than the numbers on the boxes.

Irish

Just curious, and since you reload I would assume you did a pre-shoot barrel clean, but I'm just wondering if the barrel has some "newbie" short term barrel copper build up that may be causing your pressure issue? Maybe give it a copper treatment just to see what's in there?

FWIW

Dave

Thanks for the idea. Yes, I did clean the barrel thoroughly before the first shot and again after every 10 shots on the first range session. Cleaned it again afterwards (35 rds) and once more after shooting 4 rds hunting. Cleaned it again after the first 51 rds were fired. That last cleaning was today. This was a prolonged process using a quality copper solvent and a Dewey rod. Let it soak for about 15 minutes after each wet patch and continued until they were coming out clean. The barrel has never been allowed to get very dirty since ammo is so scarce, I have never fired more than a few at a time, lol. The Savage bbl is not as pretty and shiny as my Remington varmint rifle, but is OK for a new barrel not yet fully broken in. It should get better after firing the first 200 or so rounds. It is true that the new bbl is a bit rough and might be contributing to the issue. After all it was on the first range session that it occurred and has never occurred since. I still wish to hear if others observe cases with split necks.

Irish

I can't find it at the moment but there was another thread (somewhere) were someone had chrony'd a number of rounds and found quite a big difference in FPS. Some of the hotter rounds also showed signs of "excess pressure" but not the kind that you have described.

Look up split cases for the hmr and hm2. It's happened to both of them, I think it may just be what happens to rimfire stuff.

I had it happen to me with both grains. It was early on and hasn't repeated. Some made a big deal about it on RFC but since then that shooter hasn't bothered to comment on if it is chronic or just at 1st.

I still have only fired 51 rds from the .17 WSM B-mag. On my last range trip, I saved 7 cases for examination later. Finally got around to looking at them closely. Two of the seven had cracks. One was a minor split at the neck that I would not worry about at all. The 2nd was split from the neck clear down the case to about halfway to the rim. That was ugly. I did nothing to it. It is just as it looked after firing. I still consider my bbl to be in the break-in phase, but wanted to share this pic. Be sure to wear you eye protection lads.

Irish



http://img.photobucket.com/albums/v3...crackphoto.jpg

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Originally Posted by JG26_Irish

I still have only fired 51 rds from the .17 WSM B-mag. On my last range trip, I saved 7 cases for examination later. Finally got around to looking at them closely. Two of the seven had cracks. One was a minor split at the neck that I would not worry about at all. The 2nd was split from the neck clear down the case to about halfway to the rim. That was ugly. I did nothing to it. It is just as it looked after firing. I still consider my bbl to be in the break-in phase, but wanted to share this pic. Be sure to wear you eye protection lads.

Irish



http://img.photobucket.com/albums/v3...crackphoto.jpg

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I'll get around to snapping some photos of mine and post them.

I had this problem too and searched it and came up with this thread. So, it is not just your rifle, but obviously there is a problem here. I would think this would cause a significant amount of pressure and stress on the chamber. I sent a picture as an attachment to an email I sent to Winchester. I am new here and I'm not sure how to post a picture, otherwise I would show a picture of one of mine.

http://s763.photobucket.com/user/jas...c0d5c.jpg.html

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Originally Posted by disturbed1

I had this problem too and searched it and came up with this thread. So, it is not just your rifle, but obviously there is a problem here. I would think this would cause a significant amount of pressure and stress on the chamber. I sent a picture as an attachment to an email I sent to Winchester. I am new here and I'm not sure how to post a picture, otherwise I would show a picture of one of mine.

http://s763.photobucket.com/user/jas...c0d5c.jpg.html

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For what it is worth, I have had my B-mag for about 6 months now and shot it a good bit during squirrel season. I have not kept count but would estimate that is has digested about 150 rds now. I have not noticed a split case since the first 50-60 rds. My best guess is that the inner barrel surface of the Savage is not very smooth and this was causing some pressure issues during the break-in phase. Also only seemed to be present with the 25g heavy bullet ammo. The 20's never did this for me. It is a nice shooter and a great light weight hunter.

Irish

I am having the same problem with split cases and extreme powder blow-black on with the WSM 17 ammo as well.
Recently I shot 5-15 rounds from 4 different boxes of ammo and each box produced at least one split case and 3 of the four all showed extreme power blow-back on the brass. Only one box had clean brass when ejected.

I have contacted both Savage and Winchester and Winchester as requested the boxes and split brass be sent back. I just don't know if this is an issue with the rifle or ammo. I should mention that I see this on both of the 2 B-MAG 17s I own.

Not seen a single one.

When I called savage about mine shooting better then 4 MOA @100rds and case splitting, I was told to send the rifle back and that Winchester knows about the case splitting problem and that Winchester was replacing the ammo.

I set mine back the last week of March and Savage told me they were going to replace my rifle.....Have not seen it yet!!!

Jambo, how many rounds has your rifle digested to date? and what was your break in and cleaning procedure? All of these variables may contribute to the case splitting issue. The Savage bbl as new from the factory is not all that smooth, and was not hand lapped since the cost of such is prohibitive in a low ball market entry level gun. As such, the break in often results in excessive copper fouling even when the careful break in shoot/clean/shoot method is followed to the letter. Any appreciable fouling increases the chamber pressures and can result in a split case. The very small .17 cal bore does not need much fouling to be significant. After break in if the bore is not meticulously cleaned it can/will become fouled which could result in repeats of the split cases.

My rifle was one of the first to exhibit a split case. I saw several during the first 100-200 round thru the gun. Some severe but most just a split neck. It does reinforce the need for eye protection does it not? Following the early experience with the gun, I adopted a detailed cleaning regimen after every use of the weapon. I have not seen a split case since. I would attribute this to the bbl becoming smoother, which in turn reduces both pressures and fouling and my efforts to clean it well so as to keep fouling to a minimum. That is not to say that Winchester is not running their ammo at the limit of its allowable pressures. I know not what their limits are or what the current loads are generating. But in my view, they do not have a problem. The problem is the combination of low ball rifle/bbl meeting a hot rod cartridge and then getting placed into the hands of a lot of shooters who have never owned a 17 cal gun before. The unforgiving nature of this combo is resulting in a higher then usual incidence of such problems. Many of the new owners have never owned or fired any of the 17 cal centerfire weapons. Since it is a rimfire rifle, they tend to treat it like a 22 instead of treating it like a hot centerfire. That is my take on this issue.

Solution? Spend about a week cleaning your bore. Then if it is not fully broken in, shoot a few hundred rounds thru it, cleaning periodically. After this clean it very well again. You should see some significant improvement. If it is already well broken in, then a long cleaning session may be all you need.

Irish

Irish et al,

Thank you for your responses and suggestions.

I actually have two B-Mags and the case splitting, and what's more concerning, the extreme blow-back, is prevalent in both rifles.
Each rifle has had 300-400 rounds shot through them with a cleaning after each 150-200 rounds. What is interesting is, I had one box of ammo that showed signs of blow-back on only about 10 of the 50 cases that were shot, but did result in 3 split cases.

I have contacted both Savage and Winchester about the issue. Winchester got back to me within a day and has requested the unspent ammo and split cases be sent to them. I have yet to hear back from Savage, now going on a week.

I'll keep you all update on what I hear from Winchester and Savage, if I ever do hear back from them.

Jambo

I have seen brand new .270 case splits that mirrored the picture on this thread.
The very first shot in a brand new rifle, yet.
Then, there were no others.
When the smoke rolled up on that first one, I about had a heart attack.

I think that the splits and the non-sealing, blackened brass comes from the same problem, and that is, over worked brass
in the manufacturing stage. So hard that it won't expand and just splits.

Those that seal up and stay clean, as stated in the previous posts, don't split.

It's a manufacturing problem, not pressure, I believe.

I see the same thing all the time, especially in small bore brass headed, shotgun loads.
They screwed up on their annealing regimen during manufacture.
Starting with a nail gun hull, it doesn't surprise me at all.

Finally got my HB sighted in today.
No .17 spud for the bore sighter, so took a few more rounds.
15 got it exactly where I wanted it, and 4 more confirmed same.
One case mouth had a slight roll over, inside at bullet seating, apparently.
Still the same after firing and all sealed properly with no splitting of cases anywhere.
Good to go, still waiting for the Franklin Armory AR in the same caliber to get here.
Anxious to do a little comparison.