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-   -   Checking ammo (https://www.rimfirecentral.com/forums/showthread.php?t=1176521)

squirrel1 11-10-2019 10:53 PM

Checking ammo
 
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Will experiment some soon at a few targets.
And see what results are gotten.
Definitely can see some cartridges that are way out.
Used my crossbow bolt checker and a insert out of crossbow bolt. Allows bullet to rest on ogive.
Glued insert to frame of jig.
We’ll see if any positive results are obtained.
Also will shoot some of the longer and the shorter later on to see how poi is affected.
Likely will shoot at 50 yards.

I am allowing for some allowable tolerance. Some are .005” or more long and short though. Allowing for +- .002”
May change this though depending on results.

Need to see if my gun likes longer or shorter of the ones deemed way out of whack. Might be able to use whichever on squirrels.

Btw checked 2 different lots of cci.
One is better than the other as far as keepers based on my testing. Substantially better actually.

squirrel1 11-10-2019 11:04 PM

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Here’s pic of one that is substantially shorter. See meter.

squirrel1 11-10-2019 11:13 PM

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Look how short this one is.

squirrel1 11-10-2019 11:18 PM

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Pic of long one.

squirrel1 11-10-2019 11:27 PM

Wish I had a good modern crony.
Would be interesting to see if longer are faster on average and shorter slower.
Or maybe even vice Versa.
I know this much.
Every now and then my cz455 is noticeably harder to unbolt with some rounds fired? Like round has more pressure. Could this be one of the longer rounds getting more into riflings increasing pressure"??

Only one split case with this rifle lilja barrel setup out of around 700 rounds. It was a cci. Have shot some hornady thru it just not as much.

Have gotten just shy of 4 boxes of 50 (likes about 10 rounds) ammo that meets my set allowable tolerances. Took 6 boxes of 50 to get. Used 2 boxes of different lot number. It had more shorter rounds vs other lot I used.

May show some video with this project.
We’ll see. Need some light winds. And not be freezing cold. Trigger finger don’t like that at all.

gmd1950 11-11-2019 07:52 AM

I'm sure your results will interest a lot of us.:bthumb:

squirrel1 11-11-2019 08:37 AM

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Okay went back and rechecked all ammo I checked earlier.
6 boxes total was sorted.
Younsee 3 full boxes and a partial 4th. Looks like 181 rounds. These rounds fall into area lengthnwise were majority of ammo sits. All is +- .0015” of one another.

The other boxes.
You see one labeled L= long.
These are generally .002-.005 longer than the almost 4 boxes above.

You see box labeled S= short.
These are generally .002”-.004” shorter than the almost 4 boxes above.

Younsee Nox labled EES= extremely extremely short and ES= extremely short. These are in same box but separate (one group in one end and the other in the other end.
The EES are in excess of .007” short of the baseline.
The ES are generally .004-.006” short of the baseline.

Goal here is to see what my gun don’t like.
Remember this is NOT overall length of cartridge. Rather measurement of from back of case to bullet ogive. I am not too worried about rim thickness.

I may be able to see quickly what gun likes or doesn’t like.
I especially want to see where the EES and ES ones go poi wise.
The short ones may turn out to work fine.
Will be watching the longer ones too.
And bolt opening pressure depending on which length cartridge is shot. To see if a pattern ensues.

Will try to allow at least 2 minutes between rounds when firing group of 5.
Then give even more time before proceeding with more 5 shot groups.

squirrel1 11-11-2019 11:22 AM

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Alright done some testing.
Results.
Longer ones shots higher on average. Noticed some hard bolt opening when fired too.
The rest shot lower on average. Talking roughlybullet width here for difference.

Two worst shots. One was with longer and one with EES one.s
Long ones not the ones for this rifle/barrel setup.
Long ones don’t hold left to right poi as good as shorter.
My best guess.
If I could go back and keep my baseline at zero on the meter and include all that meet it and those that are shorter excluding the EES ones I am in business.
Remember this for my gun, yours might be different.
Testing done at lasered 45.5 yards. It showed me something. Longer distance shooting might show me more. For now good enough. Wind is building for this storm coming in.

So based on what I saw. The lot number with higher number of shorter rounds is better for me. I do realize there are other factors besides bullet seating depth.
But I think I have helped myself some here.

Cheers.

I’ll sort 2 more boxes and let’s just see how many I have to discard as not so good based on what I saw this morning. I’ll try this second lot number I have.

Just for the gee whiz.
Here’s a 7 shot group at 45.5 yards with cartridges noted above as labeled short. That’s a 1” dot. Aiming at top center edge. Nightforce maxed at 10x parallax dialed out. Not off of bag rest either. I used something else so gun would be held exaclty the same every shot. Shot in far left not part of group.

squirrel1 11-11-2019 11:40 AM

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Here’s 6 shot group with what I deemed as baseline ammo when I measured.
Still at 45.5 yards.
Remember it’s possible one or more of these rounds was as much as .0015 above my zero baseline.

squirrel1 11-11-2019 11:46 AM

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Here’s 7 shot group with cartridges deemed as long above. Still 45.5 yards.
Special note.
When changing ammo designation, I would shoot a group first. Then shoot a few groups again with the designated ammo. To draw my conclusions. I think it made a difference by doing. First group when changing didn’t seem to be as bad as the ones that followed.
Temps here higher 50s low 60s when shot. Slight right to left wind. Pretty constant speed wise.

squirrel1 11-11-2019 12:41 PM

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Okay here is a new box that was sorted. You see what’s left after getting the ones out that didn’t pass. Kept all reading 0 and lower on meter. Most checked at 0 to .003” below zero on meter. One cartridge was .010” below zero I removed it. Only lowwer reading removed.
Lot number if my eyes aren’t lying to me is J12A303.
So 8 were pulled, not bad.

Will do another box same lot and see what happens. Using same standard for pass/fail.

squirrel1 11-11-2019 12:55 PM

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Another box checked same lot number J12A303.
Removed 12 rounds.
None removed due to being excessively short.
Saw one that was .005” past zero.
Had around 6 rounds I removed that just were .001” past zero for length.

squirrel1 11-11-2019 01:09 PM

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One more new box checked same lot number. J12A303.
Had to remove 11.
One was removed for being .009” short below zero on meter.

squirrel1 11-11-2019 01:40 PM

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Okay.
Here’s one 5 shot group at 45.5 yards using 5 rounds out of one of the boxes lot # J12A303 I sorted.
Some right to left wind. Again not off a bag rest instead rest in pic below.
Worst shot had good lright to left gust come in on it.
You don’t want to be squirrel and let me see him with this rig. Lol

Will be a few days until wind rests.

Btw the 455 with lilja hm2 barrel is torqued 20” lbs in front and 24”lbs in back.

Markbo 01-17-2020 03:40 PM

Very telling. For those of us that don't have a big, could you possibly measure OAL just to see if tney are falling within your specs? I can easily measure OAL but don't have a big to hold a load round. Maybe a trip tonthe hardware store with a round in my pocket is in the offing. :D


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