Trimming every loading

[rksimple]

I'm used to trimming every other time in most rifle cals I reload for. This last weekend in Vegas, I had issues I've never experienced before. I had ammo loaded that was on its 4th firing and had been trimmed after its 2nd firing. I also had ammo on its fifth firing, freshly trimmed. As soon as I began using the freshly trimmed stuff, I started missing like crazy. I zeroed 4 stages and hit a hostage. Luckily we had a 100 yard paper stage which I used to re-zero and saw that I was about 1.5 minutes high and 1 minute right.

So, anyone else had this problem? I've never experienced this in my 308 or 223. This is the first time I've seen this in my 260 as well. It hasn't happened after other trimming cycles. Any ideas?

 

[ChadTRG42]

Re: Trimming every loading

No, that's too much of a POI shift for trimming. Even if we are talking about a lot of difference between the cases. If the case necks have not been annealed, and you are getting different neck tensions, plus the varing length, it might.
Did any weather changes happen during the match? I would look more at the enviromental factors to see if that changed. The times I get a POI shift in a match is normally due to hotter/colder temps, pressure changing, ammo/powder temps. This would have more effect than the neck lengths.

 

[Clark]

Re: Trimming every loading

I have lots of project guns and I help other people with their guns at the range.

Half of the problems with my guns and theirs are caused by the screws holding the scope mounts to the receiver are loose.

 

[Victor N TN]

Re: Trimming every loading

If everything else is tight, are you sure of the glass? Could it have been dropped or otherwise damaged? I agree with Chad. That's a lot to put off on long or short brass. If the brass were exceptionally long it could be acting like a heavy crimp if it catches on the "case mouth" cut of the chamber. Unless it's a custom barrel / chamber, I don't know if it could act like that.

 

[rksimple]

Re: Trimming every loading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">No, that's too much of a POI shift for trimming. Even if we are talking about a lot of difference between the cases. If the case necks have not been annealed, and you are getting different neck tensions, plus the varing length, it might.
Did any weather changes happen during the match? I would look more at the enviromental factors to see if that changed. The times I get a POI shift in a match is normally due to hotter/colder temps, pressure changing, ammo/powder temps. This would have more effect than the neck lengths. </div></div>

Nope. No weather changes to cause that. I was shooting a KYL stage when it happened. My first two rounds of kyl were my non-trimmed rounds and were center punches. My 3rd shot on the kyl stage was a freshly trimmed one. It missed. Within 20 minutes, I missed 6 more times at 200 and 300 yards. I don't do that. After I rezeroed, everything was consistent. After zeroing, got the highest score on the 100 yard barracade and 7 of 8 hits on chaos with the second fastest time. It wasn't the mounts and it wasn't me.

So you don't notice a big shift like that after trimming? I'm not annealing, and haven't noticed any other changes like this before in 5 firings on the brass. WTF?

 

[rksimple]

Re: Trimming every loading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">If everything else is tight, are you sure of the glass? Could it have been dropped or otherwise damaged? I agree with Chad. That's a lot to put off on long or short brass. If the brass were exceptionally long it could be acting like a heavy crimp if it catches on the "case mouth" cut of the chamber. Unless it's a custom barrel / chamber, I don't know if it could act like that. </div></div>

Its just a 260 Rem match chamber. It just really has me scratching my head as this is the first time this ever happened to me and cost me the match. And I did suspect the glass, but all the misses IMMEDIATELY started when I went to the trimmed ammo.

 

[Victor N TN]

Re: Trimming every loading

Maybe you need to segregate the brass and keep them seperate until you figure out what it is. And be sure to let me know if you ever figure it out. I would appreciate the information.

 

[rksimple]

Re: Trimming every loading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">Maybe you need to segregate the brass and keep them seperate until you figure out what it is. And be sure to let me know if you ever figure it out. I would appreciate the information. </div></div>

I will post an update when I figure it out. For the 6th firing, I will trim some and leave some untrimmed. Hopefully I'll get it squared away.

 

[Swan]

Re: Trimming every loading

Hope you get it figured out. I can vouch for his mystery misses as I was spotting them from his right when it happened. No drastic changes. I too wonder if the neck tension was variable between the two loads and that was a possible contributing factor... who knows.

Btw, maybe you should wait til after next months match to fix the problem.

 

[rksimple]

Re: Trimming every loading

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Swan</div><div class="ubbcode-body">Hope you get it figured out. I can vouch for his mystery misses as I was spotting them from his right when it happened. No drastic changes. I too wonder if the neck tension was variable between the two loads and that was a possible contributing factor... who knows.

Btw, maybe you should wait til after next months match to fix the problem.

</div></div>

Well, I'll be in Sacto next month so I'll give you guys a break. LOL. Thanks for the spotting bTW.

In thinking about it a bit, the sharper edges of the trimmed brass may have been the culprit. I'll know by this weekend.