This is topic Suddenly, a sour load in forum Firearms forum at The New Huntmastersbbs!.
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Posted by Leonard (Member # 2) on February 22, 2003, 02:03 PM:
I have a gun that is going through a workup for a new bullet, and using an established load as a control.
The new load is performing very well on paper, velocity is better than expected.
Then we have the original load that I've been using for several years, without any complaints. It's not satisfactory, right now? This isn't a new batch, it's existing cartridges that were loaded more than a year ago.
Then I tried a different established load, also assembled over a year ago, and the accuracy is still exceptional.
What could have gone wrong? I don't want to pull them and reseat them longer, to compensate for possible throat errosion, as that may alter the conditions, and I won't know anything. However, it may be the only solution if I want to continue using these 400 or so bullets.
Throwing them away is not a problem, either. I'm just puzzled. Any ideas?
Good hunting. LB
Posted by DAA (Member # 11) on February 22, 2003, 03:16 PM:
Leonard,
The new load, the old one no longer performing, and the old one still performing. Are they all of the same components, except for bullet and/or powder charge?
Or are they different powders? If so, did you clean before switching to a different powder? If not, are the two "old loads" both the same powder and the one that still shot good was the second one tried? Switching powders while testing, without cleaning, often leads to poor groups until the bore gets "seasoned" with the new powder type.
Relationship to the lands, as of last time you checked, still the same for all 3 loads? Or different? Obviously, a tuning variable, is it possible that the new load and the old one that is still doing well have a similar ogive to leade relationship, while the other old one is odd man out?
Any chance that the old load that isn't performing has been subjected to different conditions than the one that is? "Cold weld" can change the performance of stored ammo, and can vary a great deal according to conditions. If one batch has been hauled around a lot, while the other sat home on the shelf?
Just how signficant was the difference and deterioration in performance? A couple tenths, more? How were conditions?
Obviously, I haven't a clue, and am just groping around for one ![[Big Grin]](biggrin.gif)
.
- DAA
Posted by Leonard (Member # 2) on February 22, 2003, 05:27 PM:
Leonard,
The new load, the old one no longer performing, and the old one still performing. Are they all of the same components, except for bullet and/or powder charge?
**** the new load uses the same powder (R-22) and weight, same case, same primer, but the new bullet is 3.5 grains lighter than the old bullet. The third load uses a significantly lighter bullet and different powder, (AA 2700) but same brass and primer.
Or are they different powders? If so, did you clean before switching to a different powder? If not, are the two "old loads" both the same powder and the one that still shot good was the second one tried? Switching powders while testing, without cleaning, often leads to poor groups until the bore gets "seasoned" with the new powder type.
**** of course, I cleaned between all loads at ten round intervals.
Relationship to the lands, as of last time you checked, still the same for all 3 loads? Or different? Obviously, a tuning variable, is it possible that the new load and the old one that is still doing well have a similar ogive to leade relationship, while the other old one is odd man out?
**** the orig. load with the problem, I haven't checked real recently. The test load is .005" off and the other old load is way off the lands because it is 25 grains lighter, and shorter, but it never affected the accuracy because it is already the most accurate by a good amount.
Any chance that the old load that isn't performing has been subjected to different conditions than the one that is? "Cold weld" can change the performance of stored ammo, and can vary a great deal according to conditions. If one batch has been hauled around a lot, while the other sat home on the shelf?
**** That is a possibility. It would be difficult to determine unless I check. The old accurate load has been hauled aroound and subject to temperature fluxuations, but not nearly as much.
Just how signficant was the difference and deterioration in performance? A couple tenths, more? How were conditions?
**** Conditions, variable wind ten to twelve mph? Test load is averaging under a half inch with five different powder charges. Sour load used to do about the same but it has been over an inch the last two times I fired it. The third load with the light bullet and different powder is closer to .375" consistantly, with an occasional quarter inch (X5) Ambient not a factor.
Obviously, I haven't a clue, and am just groping around for one .
- DAA
****Damn, I was counting on you! ![[Frown]](frown.gif)
Good hunting. LB
Posted by DAA (Member # 11) on February 22, 2003, 05:51 PM:
Hmmm... New bullet is a bit lighter, old load that is shooting well, much lighter.
That's a lot of difference, something has gone pretty badly wrong. But it obviously isn't systemic - the rifle still shoots.
Any chance that the load gone sour is using a bullet that is marginal for the twist? That is, heavy/long. If it was just barely getting to sleep to begin with, it could be that the throat getting rougher with use has pushed it back across the ragged edge? Of course, it would have had to be a very close thing to start with. Jacket damage from a rough(er) throat is a pretty small variable in stabilization. If it's a bullet that should be fine, I'm definitely off in the weeds here. But if it WAS a close thing to start...?
- DAA
Posted by Leonard (Member # 2) on February 22, 2003, 07:29 PM:
Yeah, that's what has me stumped. Just sitting there on the shelf and suddenly, a dependable load that I've been using for years?
These things are usually gradual, barrel errosion, even a bedding problem, but then again this gun doesn't have a thousand rounds through it, with this barrel.
The twist is 1 in 13 which is more than adequate for a 100 grain bullet at this velocity 3600/4000.
As near as I can tell, it is the load that the gun doesn't like, but there was never an indication that it was marginal as far as stability.
As I said, just for curiosity, I can load a few more, I still have maybe three pounds R-22 from the original lot, and seat them right on the lands, maybe that will show either pressure or an accuracy improvement?
Beyond that, I'm still fairly happy, at least for now?
Good hunting. LB
Posted by Terry Hunter (Member # 58) on February 23, 2003, 03:23 PM:
You said the powder was from the same lot.Is it the same container or a differant container.
Posted by Leonard (Member # 2) on February 23, 2003, 04:47 PM:
I can't exactly answer that, Terry. I bought the powder in one pound plastic bottles and consolidated the powder since there was a lot of extra room and I am a little short of storage space. In other words, the powder is marked the same lot and I blended it a little. LB
Posted by GMB (Member # 109) on February 25, 2003, 12:03 PM:
Leonard;
Seat the bullet out further . See if you can touch the lands. If you can't seat it out as far as practical. The throat maybe washed out or worn. This may help.
Posted by GMB (Member # 109) on February 25, 2003, 12:16 PM:
Sorry, did'nt read the last part of your post. You might seat the bullet a little deeper maybe .002 or so just make sure you move the bullet. If the loads have been loaded for some time the tend to weld themselves together[case & bullet]. Seating them deeper will break the bond. If they are bonded together this will cause high pressures and accuracy will suffer.
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