What is going on???????

[toddc]

The target you just posted is certainly encouraging.

I have to ask. You said the brass was .010" too long. Compared to SAMMI length? Or .010" longer than your chamber end? I would suggest to you that you are far from the end of the chamber UNLESS you actually measured it. Most chambers, unless made with a custom reamer, have a huge distance to the end of the chamber compared to SAMMI max length specifications.


I would suggest there was something else at play here. Sure if all cases are the same length and diameter then they should have very similar bullet tension/ release characteristics which would help create consistent velocity and better accuracy. Might not be able to see this with a hunting sporter but everything helps.

What Varmint Al says on his site is true, I found the same sort of dimensions:

Quote:
"I usually find that the factory recommendations for case length leave a 0.050 inch to 0.070 inch gap between the end of the case and the actual length of the chamber."

link to how to measure chamber length.
Varmint Al's Handloading/Reloading Page




The question remains, what has the rifle shooting better now? I think you should repeat the testing for a larger sample.

This is the beauty of this site, Len has the notification system so we never miss an entry. We posters offer suggestions to the OP and we all learn. Keep us informed Creedmoor shooter.

Prime reason for a chamber casting.

 

[elkaholic]

Yes the target is definitely encouraging. Getting more to where I like to see it. As for the case lengthat according to ther hornady manual my max case lengthe was supposed to be 1.920. I was running around 1.930-1.933. I have not measured my chamber length. I will test some more rounds and see if the results are the same. Something definitely changed no doubt about it. As I suspected the H4350 was going to shoot better being so cold out. I'll try some more rl-17 and h4350 to see what I get for results. Any other suggestions are most helpful!

I was going to ask the chamber length question too. It sounds like, at most, you may have been .003" over? If some were .003" over and the rest were right at or below chamber length, that could cause fliers.

 

[Creedmoor shooter]

I was going to ask the chamber length question too. It sounds like, at most, you may have been .003" over? If some were .003" over and the rest were right at or below chamber length, that could cause fliers.

That very well could be. My 7mm RM has been acting weird as well and I checked my cases and those are all .015 too long as well so that's the common denominator. I'll shoot my Creed some more probably once this cold snap is gone by and I'll post my results.

 

[Creedmoor shooter]

My rl-17 load definitely opened up so I'm thinking between that and the brass it was causing my erratic results. I'm assuming with rl-17 being more temp sensitive than h4350 I've fallen off my node due to the cold weather. I'll retest my 42.5 load as well as a 43 grain load to see if that will get me back on my previous node

 

[LoneTraveler]

I agree if a few o the cases is over length could cause squeezing the neck in the chamber and cause pressure changes.
Have you just checked barrel free float on the stock with the rifle standing vertical or in shooting position? Put the rifle on the bipod and to your shoulder in shooting position and have some one check the barrel free float. The stock may be flexing and causing contact with the barrel. or if the rear screw is not torqued right. Just another thing to check. Good Luck on finding the problem and the cure.

 

[Creedmoor shooter]

I agree if a few o the cases is over length could cause squeezing the neck in the chamber and cause pressure changes.
Have you just checked barrel free float on the stock with the rifle standing vertical or in shooting position? Put the rifle on the bipod and to your shoulder in shooting position and have some one check the barrel free float. The stock may be flexing and causing contact with the barrel. or if the rear screw is not torqued right. Just another thing to check. Good Luck on finding the problem and the cure.

Yes I checked fhe free float in the shooting position. I could fold a piece of paper 3-4 times and it still fit.

 

[tbrice23]

That very well could be. My 7mm RM has been acting weird as well and I checked my cases and those are all .015 too long as well so that's the common denominator. I'll shoot my Creed some more probably once this cold snap is gone by and I'll post my results.

The only way to know if your brass is too long is to make a chamber cast ( as mentioned earlier) or make a chamber length gauge.
Cut half the neck off of a case with a dremel, seat a bullet in the case, ream the cut off half of the neck to have .001" tension , then slip the cut off piece on the bullet long. Carefully chamber and very carefully eject the round ( help keep the round from draging on the action while chambering and ejecting) .
Measure and repeat until you get a consistent measurement.

Every chamber I've ever had was at least .030 longer than book max. ( except one which happens to be a Criterion 6.5-284 Norma ).

 

[Creedmoor shooter]

Well we had a break in the weather and I was able get out and test again. I did the same exact loads as last time. 42.5 of rl-17 and 42 grains of h4350 all with the 140 eld-m. The rl-17 load didn't change. High .6s. I was hoping because it was 40 degrees I'd see it tighten back up. The H4350 however did fantastic. I will mention that I did do a full length resize this time around. I normally neck size but my rounds were getting harder to chamber so I did a fl resize then I'll go back to neck sizing. I'll stick with this load til the end of winter then get back out I. The spring and test rl-17. Thanks everyone for your time and help!

 

[tbrice23]

Do yourself a favor, try staying with FL sizing just bumping the shoulder 002". The name of the game is consistency. If you change your sizing routine you'll have to fire all of your cases to get back to neck sizing.
I even full length size ( correctly) for my Benchrest rifles.

Just a suggestion.

 

[elkaholic]

Do yourself a favor, try staying with FL sizing just bumping the shoulder 002". The name of the game is consistency. If you change your sizing routine you'll have to fire all of your cases to get back to neck sizing.
I even full length size ( correctly) for my Benchrest rifles.

Just a suggestion.

+1 on that

 

[Creedmoor shooter]

I honestly haven't noticed much of a difference when I fl resize my cases every 4-5 firings. Maybe if I was a serious bench shooter. I'm assuming there's I tool I need for measuring shoulder bump? I do like to be consistent with everything I do on the bench so this is something I want to look into.

 

[AZShooter]

No special tool necessary. Just progressively lower FL die or body die till case fits to your satisfaction. Could have a tiny bit of bolt closure resistance or none your choice. Obviously with a hunting rifle with a chance for fast followup shots no bolt closure resistance is helpful.

Once you get the die set don't rely on the setscrew to hold the lock ring in place. Instead get a set of feeler gauges and precisely measure the gap between the die and shell holder. I place the individual gauges in the die box. Use same shell holder each time.

 

[Radhimself]

My 7rm did the exact same thing

Neck tension was my issue...

 

[Creedmoor shooter]

Well I figured I'd post an update. The rifle has been shooting alot better. I'm not exactly sure what was wrong but it's shooting very well. I trimmed my brass and did a fl resize then went back to neck sizing and it's shot very well. .2s with the 140 eld-m and yesterday I tried some 130 berger vlds I had kicking around and I was very surprised with the results. Pic below of how they did.