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Thread: Sako 85 Kodiak .375 magazine denting case shoulders

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    Member ekberger's Avatar
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    Default Sako 85 Kodiak .375 magazine denting case shoulders

    I would like to share an interesting finding that I've noticed with my Sako 85 Kodiak .375 H&H, i.e., dented cartridge case shoulders in the magazine that seem to be related to the design of the removable magazine. I have other Sako's including .375 H&H's and they all have the spring bottom loading magazines, but this design has a separate removable magazine that holds 4 rounds in the magzaine and one in the chamber.

    I've been loading for and shooting lots of rounds through this gun so I'm pretty familiar with it. All of my shooting has been done with my own hand loads so I don't have repeat data with factory ammo. In general, all cartridges were loaded with Barnes 300 gr. FB TSX's in the range of 69-70 grains of RL-15, CCI 250 primers, therefore everything is within posted standard reloading specifications. There were no signs of any excessive pressures during shooting either with the gun or visually on the cartridges which I carefully watch for.

    Because I have been paying attention to COAL's as I've been working up loads, I loaded the magazine with cartridges with premeasured COAL's so that after firing 3-4 rounds I could measure the last couple rounds to see if there has been any bullet movement as a result of recoil. However upon inspection, I have frequently noticed dented shoulders on the rounds remaining in the magazine. When I first noticed this I didn't fire these rounds because I thought that I might have caused the dents during loading. The problem of denting cases is well documented in the reloading literature as sometimes being caused by excessive lube on the case during resizing. So when I first discovered this I just pulled the bullets and tossed the cases, however, it showed up time and time again so I know that was not the problem.

    What I'm convinced is happening is that the cases are being dented in the magazine during recoil of the rifle. Take a look at the photos and you can easily see where this is happening and what may be causing it. Unless you look at unfired rounds you would never notice this because I have also observed that fire-forming the rounds pushes the shoulder dents out as the case expands to fit the chamber. I have no data however, I am concerned that denting may weaken the shoulders on the cases and/or cause accuracy issues. I've frequently seen cases with 2 dents perhaps caused by the cartridges rotating in the magazine during firing.

    Again, this never happened to me with the bottom spring style magazine clips vs. the removable magazine on this gun. Admittedly this gun has a significant recoil so one may never have similar findings on a smaller caliber rifle. I have attempted to contact Baretta, Sako's owner and importer but they have not responded to any of my inquires. I would be interested to know if anyone else has observed similar findings or has another plausible explanation for what I am finding.

    Eric
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    Member pinehavensredrocket's Avatar
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    this is an interesting problem...and your preliminary findings appear grounded in your pictorial display of the loaded magazine. it would seem obvious that beretta (by way of sako) tested this magazine design and passed it as acceptable. i think it wise to contact them for their evaluation into the offending magazine.

    as you related, the recoil is substantial and the cartridge case damage is not coincedental but is repeatable.

    reloaded ammunition (high pressure) neck sized on the shoulder may find a weak spot causing a premature crack or blow-out. this of course could be dangerous to the shooter and the firearm.

    beretta lists a number ( 800-929-2901) and a customer service header on their web-site. good luck!
    happy trails.
    jh

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    Member hodgeman's Avatar
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    Just wagering a guess here but... I'm thinking Sako wasn't too concerned with the culmalitive detrimental effects of the dents as it pertains to reloading. Several manufacturers use design features that are hard on brass.

    Looking at the photos, It appears the magazine is designed to keep the bullet tips from mashing themselves into the front of the magazine.

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    ek,
    Clearly the distance in front of the TSX is allowing the entire shell to slam forward into the front wall of the magazine. The indented magazine is stronger than the brass and collapsing the shoulder area. While it may fireform back into shape, it also could induce a failure to feed smoothly - in a touchy situation that could be bad. That is a substantial dent!
    1. Could you seat a longer COAL to prevent the forward movement BUT still have optimal accuracy? Usually you want at least .050" off the rifling with the TSX's.
    2. How does your COAL differ from the factory 300gr. FB TSX?
    3. I have scene a scenario where a shim is applied to the inside forward wall of the magazine to "use up some space".
    This would be the other version of #1.
    4. I'd try to call Beretta but don't hold your breath.
    FYI, the third cartridge in my Kimber Talkeetna (375 H&H) will be about .015" shorter after the first two get sent off.
    That is with the 270gr TSX's.
    Keep us posted on what you find out and what you end up doing.

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    Member ekberger's Avatar
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    knikglacier, thanks for your comments and ideas. Yes, I need once again to try and contact Beretta to at least follow up on why they have never responded to any of my incident reports. This is not what I experienced from Stoeger Industries when they were the importer. I have a quick story of the later and because I brought it up I'll digress...I sent Sako rifle to South Africa in a hard case and when I opened the case up on arrival the stock was broken in half at the pistol grip. Baggage handling or poor packing on my part... nevertheless, when I got back I sent photos and and a report on what happened to Stoeger and they said to send it back to them. To my surprise, in less than a month they had returned the rifle with a new stock, no questions ask and at no cost to me. I'll leave it to the readers to ponder whether or not we'd get that service in todays world.

    Yes, I have worked up these loads with different COAL's, however when I noticed slight bullet movement in unfired cases due to recoil I always crimped the loads into either the first or second cannelure grove on the bullet. The images show the bullet seated to the front cannelure grove with a slight roll crimp. Following this process, I was able to get acceptable accuracy crimped into the second cannelure which gave me a longer round which fit and worked well in the action so that's possible. It's been reported that Barnes TSX bullets have good accuracy with a fair amount of "jump" so I ended up simply seating into the front cannelure which gave me a COAL consistent with many popular loading manuals. At 100 yards, I can shoot groups the size of a quarter. However, I don't have the data to answer the question about whether or not seating the bullet a little farther out would help with the denting. Intuitively, wouldn't the bullet simply hit the front of the magazine and with recoil push the bullet back. Isn't this the same scenario I would face with your comment about "use up some space". I'll have to think about that.

    To question #2, I don't have this data, from factory loaded rounds, however, I have the Barnes loading manual COAL's and I am within these specs.

    I stated in my initial post that the loads were within Barnes stated specifications in but I failed to mention that I had all the velocity data on these loads as well which also are in-line with published data. Briefly, at 69.5 grains of RL-15 average velocities are around 2400 fps with a 300 grain bullet seated into the front cannelure. I have data which show velocities on average around 2500 fps when I'm seated at the second cannelure grove, which is expected.

    Eric

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    Eric,
    My reason for the longer COAL would be to prevent the bullet/case from getting any momentum by using up the "airspace" with a longer COAL. If the bullet is say, .010" - .020" away from touching the front wall of the magazine, it can't get up the speed to bang the wall with enough speed to allow the shoulder to be dented. You might get a scratch on the brass in the shoulder area but not dent. You can't make it a tight fit because that may impede reliable feeding.
    I suppose that crimped wall of the magazine is to aid in feeding of the cartridge. A single stacked magazine would not need to have those crimped magazine walls but that doesn't help you with this rifle.
    Either way, cases dented to that extent cannot be tolerated.

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    Knikglacier, thanks for the further explanation, I understand. Following your post I took some measurements and I can increase the COAL easily by crimping into the second cannelure grove. I may have to back down my load a bit because I have data on pressure increases as COAL changes (increases). Taking it out any further would not allow me to get the crimp that I think is wise and recommended in high caliber guns. That may help. I have data on load accuracy so that won't suffer. The length of the magazine limits my flexibility somewhat.

    However, to the crimping and COAL point, I have some data with Swift A-Frame 300 grain bullets. Crimping into the single cannelure on that bullet would give me relatively the same COAL that I have currently with these Barnes bullets and set me up with the same scenario. In other words, if I were to increase the COAL I would not have a cannelure to crimp into. The design of the Barnes bullets provides this opportunity.

    I agree that this denting is unacceptable. I'm now concerned that these loads may be too hot, however, as stated previously, I watch carefully for pressure signs and have always backed off on the loads during development. Furthermore, velocity measurements are within published standards. What concerns me is that this denting is so repeatable. To dig further into this, I'm going to have to get some data on factory loads to do some comparisons. Even if this is happening to others it simply may not be seen unless you're pulling unfired rounds and inspecting them. Many people who own a gun like this don't do the load development and/or shoot it enough to pick up on something like this. I'm sure that Sako did the R&D when they made the changes to the magazines, I simply have to better understand what's happening here. It's just going to mean more sore shoulders.

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    ekberger,
    your current "load" (grains of powder) will do fine. When we shorten the COAL we will get higher pressures. Lengthening the COAL will reduce the pressure.

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    ekberger,
    Just additional comments. First, Eastwoods is correct, your pressure will be fine. Next, don't be concenred about the loads being over any pressure limits. Your R-15 load is under Barnes Data, even though they used a Fed 215M (hottest) and you are using a CCI 250. I actually would try a standard large rifle primer also because 70grs. of powder is in that "gray area" where some writers say a magnum primer isn't needed. A shoot off between the two would answer that.
    In my humble opinion, you cannot "read" a fired case and detect excessive pressure using the time worn indicators like primer condition. When you CAN read or see them, you are WAY OVER pressure limits. The very best way in determining that is to shoot thru a chronograph and compare your velocities with what "the book" says. If you are within "acceptable Limits" says 100 fps and the accuracy is acceptable, then you are there. I would repeat that 2-3 times and call it good. A chronograph is a good indicator as to how consistent your handloads are and how your rifle is performing compared to the published reloading data. So I do not think your loads are over the limit just because the magazine is denting the shoulders. They look bad though!
    Now you talked about Sako making changes to the magazine. I looked but couldn't find what they did. If you are talking about Sako eliminating that magazine groove, then I would check with the gunsmithing suppliers in getting a replacement.
    Lastly, those really aren't cannelures on the TSX bullet. They were engineered to decrease friction with the copper and rifling. I have never "crimped" a TSX bullet in any caliber including my 270gr TSX's.
    That's all for now.
    Last edited by knikglacier; 08-25-2010 at 18:22. Reason: Add one more point

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    A quick comment to the recent feedback which is all very helpful to me so that I can evaluate this further. Yesterday I got Beretta's attention to the matter and will have to wait to see if they follow up. Nevertheless, I will try to evaluate based on the feedback. I have a chronograph and use it during load development so have that part covered. The comment I made about Sako changing the magazine was simply a reference back to the older style where the bottom plate was hinged and the cartridges pushed up with a "Z" spring. This is the design on all of my other Sakos. The magazine we're dealing with here is a removable magazine, I should have made that more clear. I do not know if other Sakos with this removable magazine have those pushed out ridges that sit just forward of the cartridge shoulders like the one pictured. I've used Fed 215 primers (not match grade), in some of this load development, but do not have the comparisons since discovering this issue. I will have to go back reconstruct a lot of information which will simply mean burning more power and bullets. I'll follow up on my findings.

    Regards,

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    ek,
    Sounds good. I am using WLRM primers only because I have them and want to use them up. I use 67gr. Varget with my 270gr TSX's.
    Hopefully Beretta follows up on this cause it is NOT acceptable.
    Keep us informed.

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    Default Beretta's feedback on denting case shoulders

    I have had the opportunity to exchange information with Beretta on this issue for which I am thankful.

    Their initial comment about the design of the magazine is as follows:

    The typical design of a well engineered magazine box, whether of the fixed hinge floor plate design or a detachable magazine box, is the raised recoil ribs of the magazine box.

    The purpose of the these ribs is to prevent the cartridges in the magazine box from moving forward under recoil. Rifles with out these ribs suffer cartridges that have deformed bullet tips, as the bullet tip hits the front of the magazine box. The deformation of the bullet tip has a significant impact on the exterior ballistics.


    They have further gone on to state that they have not seen this finding previously nor are they aware of others who may have.

    I do not take exception to the comment on magazine design. However, further discussions with them simply point to the need for me to gather additional information that may shed light on my findings.

    Although this has been a repeatable event in my hands, I do not have data on factory ammo because all my loads to date have been my own hand loads. I simply speculated that it's repeatable. Secondly, because I have exclusively used my own hand loads, I am not able to answer whether or not I have seen this with new brass or only with brass that has been used one or more times. I have looked though my load and use data and admittedly am not pleased that I can not answer this definitively, perhaps a lesson for me. Nevertheless, I will work though this issue to see if I can determine whether or not this is something that occurs only with brass that may have been case hardened with use (something annealing may help), although during load development with a rifle of this caliber I typically do not use a cartridge more than 4 times until I have good data on the load.

    All I can say at this point is that I'm satisfied with what I have discussed with Beretta technical representatives, and that I need to gather more data to answer some outstanding questions.

    Stay tuned.

    Regards...

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    Quote Originally Posted by knikglacier View Post
    Your R-15 load is under Barnes Data, even though they used a Fed 215M (hottest) and you are using a CCI 250. I actually would try a standard large rifle primer also because 70grs. of powder is in that "gray area" where some writers say a magnum primer isn't needed. A shoot off between the two would answer that.
    I have data on the 375H&H with Eric's charge weight, we have communicated on development in his rifle prior to this post. My chronograph results with Fed 215, 215M and CCI 250 show that the 215 and the 250 are tied but the 215M is 40fps slower as tested in a Remington 375 H&H. Personally I chose the 250 because it was consistently showing a lower ES.

    Test results available on reloader bench claim Winchester is the hottest magnum primer available by as much as 2000psi over Remington which was the lightest.

    I would not use a standard large rifle primer in a magnum case that was intended to be fired in cold climates regardless of the charge weight. Eric is hunting in Alaska with this rifle and a solid ignition is paramount to safety.

    I'm attempting to understand your logic in using what you think is a lighter primer in a case that is below what Barnes claims as a max load. Are you suggesting he needs to shoot at a lower velocity? Why? If his current velocity achieved his accuracy then a lower velocity may diminish it resulting in the need for a higher charge further questioning the suggestion of a colder primer.

    Eric, just curious, what brand of brass are you loading and did you anneal these cases making them softer than normal. I've never seen a case dented by recoil.

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    I started my load development with Remington brass and saw the dents during its use. I switched to Hornaday brass and also saw dents in the cartridges so there was no difference in what brass I used. I am thinking about trying Norma brass next.

    No, I did not anneal the brass. The only thing I can't definitively answer at this point is whether or not the dents were noted on second or third fired brass and not on new brass. I'll just have to get that data. I can also back down the load and work it back up again to see if at some point, velocity has an effect. I can also try a different grain weight. I did some development with Barnes 270 grain TSX's following the loading data in Barnes manual and quickly noticed excessive pressure signs even in the mid range of their published data with RL15 so I backed off and concentrated on the 300 gr TSX FB.

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    Quote Originally Posted by ekberger View Post
    I did some development with Barnes 270 grain TSX's following the loading data in Barnes manual and quickly noticed excessive pressure signs even in the mid range of their published data with RL15 so I backed off and concentrated on the 300 gr TSX FB.
    BARNES DATA IS JUNK!!!

    If you notice the 270gr and 300gr data on the 375H&H and 375 Ruger on pages 344-349 they publish higher charge weights and velocities in the H&H than the Ruger which was designed to outrun the H&H from the start of the concept. They publish less charge and velocity in the Ruger which has a larger case with higher factory velocities than any factory H&H load.

    I have found similar issues with other cartridges in their manual so I cross reference their data in other manuals before considering it.

    Cheers

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    ek,
    Have you sent your photos of the damaged shoulders to Beretta? If so what did they conclude? The reason for the raised recoil rib makes sense but your results are unacceptable.
    In my opinion switching brass or annealing is not the answer. Annealing may make the dent larger because you are making it softer.

    What were the excessive pressure signs you saw in the 270gr. TSX load?

    marshall: My comment on the standard primer is based on some gun writers concluding that their use resulted a lower ES and excellent accuracy. The 70 gr amount is the "gray area". The writers had access to pressure test data as well as velocities. By contrast, some ball powders have performed better using magnum primers in non magnum calibers.

    Back to ek:
    I remember a buddy who had 338WM cases that looked like your dented cases. We finally figured it out. He had too much headspace and gas was escaping rearward and denting the case in the shoulder area VERY similar to yours. Just a thought. Shooting ONE shell at a time confirmed our suspicions.
    Last edited by knikglacier; 08-30-2010 at 17:20. Reason: Add one more thought

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    knikglacier, yes Baretta has seen the images. Their "conclusion" is inconclusive, if that makes any sense. They support the magazine design and although they didn't come right out and say it they suspect my ammunition. Their recommendation at this point is for me to set a baseline with some high quality factory ammo and see how my results compare. They further go on to say that if these results are repeatable with factory ammo then I might have a warranty claim. Federal Cape-Shok is loaded with 300 grain Barnes TSX with a published muzle velocity of 2470 fps. I find published velocities on factory ammo to be over rated but I'll just have to see how this performs because I can chronograph these loads side-by-side with mine. I just don't know what propellent their using. It's the closest thing to what I have if I want to do the test. Sako loads 270 grain Barnes TSX (Powerhead) in their own ammo, but the 300 grain loads are with Nosler bullets.

    I was working up 270 grain TSX loads with RL-15. I used both Fed 215 and CCI 250 primers. I had significant primer flattening with both primers and significantly more noted recoil in the mid-range of the published load data. I know that primer appearance by itself isn't conclusive, however, it's one indicator we all pay attention to. I simply did not think I could work up to the published maximums safely and backed off. I don't have enough data to be conclusive at this point so I don't want to draw any conclusions, beyond saying that if you're going to work up this load with RL-15 you approach it cautiously from the low side and in small increments. Perhaps good advice regardless. I know many use this load very successfully.

    Interesting point on the headspace. I think I'm following you on shooting one shot at a time. Obviously, I'm not seeing any problems with chambering a single round. It was just when I filled the magazine and noted this with remaining rounds after firing. The interesing point is that I often saw up to two shoulder dents. I suspected rotation of the case causing a second dent, however, that spring clip in the magazine is pretty stout.

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    Well unless we both are totally not communicating, your last paragraph settles it.
    Single round - no shoulder dents.
    Multiple rounds - one or two dents, depending on how many shots fired.
    There isn't a hoot of difference between brass hardness that is important here. Annealing or the lack thereof is also of no conern.
    The issue is what the raised recoil rib is doing to your ammo! It is obviously NOT preventing the rounds from being hurled forward during recoil with so much force that brass is dented. Once again, if the COAL was longer, this "should" prevent each unfired cartridge from getting a running start. It will be imteresting to see what the factory ammo does. It also will be interesting to see what the factory COAL is and how much space is left in front of the bullet.
    Ek, as I see it, while crimping may prevent the bullet from getting seated a bit deeper, it will NOT prevent the shoulder from getting dented.
    While you said the spring clip is "stout", maybe it is NOT stout enough to hold things in place under recoil. The recoil rib has to work with the pressure of the spring to hold things in place. Alone, the recoil rib can't do a thing.
    Keep us posted.

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    knikglacier, thanks for the follow up. I'm heading for Alaska today so dents or no dents the rifle goes with me. I'm not feeling really good about that, however, I'll complete the work up and we'll see where it goes from there...Eric

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    What about shimming (or otherwise modifying) the back of the magazine to cause the shoulder to set against the rib more closely. It seems that this would stop the cartridge from slamming around without the negative effects of a longer COAL causing the bullet nose to impact the mag front as noted previously. Perhaps a few taps in the center of the back of the mag to bend it forward a few hundredths. Also the mag width may be off a bit allowing the lower cartridge (in the pic) to slide forward at an angle under the the top cartridge during recoil and causing the tip of the rib to impact directly on the apex of the case shoulder.

    Just some thoughts...

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