DartonJager
Well-Known Member
- Joined
- Apr 1, 2016
- Messages
- 1,010
Long long time ago bought a 24" Savage 10 FCP- in .308 Winchester. Sat on it a long while. Then three years ago needed to set it up for deer hunting VERY last minuet and as I had no reloading dies, bullets, brass or powder had to buy some ammo. Only second time in my life I have ever bought factory made CF rifle ammo. Topped it with a Weaver Grand Slam 4.5-14x40mm scope.
Ended up buying a bunch of blue box Federal .308 Power Shock ammo based on the stellar reviews I found all over the internet plus it was on sale for a phenomenal price of less than .70c a round. Bought both 150 grain and 180 grain loads. Was utterly astonished how well both the 150 grain and 180 grain loads shot. Both under 2" at 300 yards one ragged hole groups at 100 yards. Even more surprising was both the 150 and 180 grain shot to the same POI at 100 and 200 yards and still close enough at 300 to not be worth adjusting the scope.
Was intending to use the rifle as an economical way to teach myself long range shooting VS using any of my belted or short mag rifles.
Earlier this year after a 3 year + search finally found a suitable good enough scope that matched 90%+ of my long range requirements at a price I could afford and bought it. Ended up buying from a member here a Trijicon Credo HX 2.5-15x42.
Mounted it on a Precision hard Core gear 20 MOA base with Warne horizontally split rings that I glass bed the bottom half of the rings.
Was down to my last 30 rounds each of 180 grain and 150 grain Federal PS ammo and was done mounting the scope so I was really itching to sight in the scope and get started shooting long range, and I had finally acquired my 308 dies but hadn't done any reloading so I stopped by my local Cabela's and surprisingly enough they had the same Federal power Shock ammo but only in 180 grain so I bought two boxes.
Three days later was at the range and after setting my scope up for eye relief and getting the cross hair vertically plumb to the barrel, started my zeroing process. As I wanted to save the Federal PS factory ammo I knew to be vary accurate, I instead used the newly bought 180 grain ammo to zero my scope.
From the very first round I loaded by hand into the chamber I noticed closing the bolt required more force than should be necessary based on shooting the other ammo. I ejected the round and then chambered a round from the other ammo that shot so well. It took undoubtedly noticeably less force to close the bolt and chamber a round with the odder ammo VS the new ammo.
Not a significant more amount but definitely noticeably more.
I used the older factory ammo and once the rifle was zeroed at 100, shot one 5 shot 100 yard group and it was true to past performance a single ragged hole group. Shot three shots of the more difficult ammo and it produced a group just over 2" C-C. Bolt didn't get any more difficult to open or close and didn't notice any increase in felt recoil.
I chose not to shoot any more of either ammo until I got home and checked the ammo.
Now this is where I get totally baffled. Using my Hornady Head Space comparator and bullet comparators I measured the loaded case lengths from base to shoulder and from base to bullet Ogive. Measure 10 different cases each of the older 150 grain and 50% of the new 180 grain ammo and here is the measurements averages I came up with:
Older 150 grain Federal Power Shock ammo:
Base to Shoulder measured 1.6185" +/- 0.0015" for ten randomly selected cartridges of the 18 left
Base to Ogive measured 2.150 +/- 0.002" for same ten randomly selected cartridges
Base to tip of bullet 2.7185 =/- 0.0155" same cartridges I understand this measurement tends to be unreliable due to significant variances in bullet length but I measured it anyhow.
New a180 grain ammo that was difficult to close bolt on measured 50% of all remaining ammo
Base to shoulder 1.6180 +/- 0.0018"
Base to Ogive 2.1225 +/- 0.0020"
Base to tip 2.7035 +/- 0.0191"
Yes you read correctly the rounds that were more difficult to close the bolt on were the essentially the same length base to shoulder and were SHORTER in the two other measurements I made. I measured every round five times each for every measurement and did an average.
All measurement are shorter all SAMMI maximum.
I then used a dry erase marker and coated the entire exterior of both different loaded casing and chambered them and noticed no significant makings on the ejected rounds. I also measured fired casings of both different loadings and again both were well below maximum SAMMI specs.
So how can Factory loaded ammo that is the essentially the same length from base to shoulder and shorter from base to Ogive AND shorter than SAMMI maximum both loaded and fired be more difficult to chamber than a round essentially longer or the same length?
Ended up buying a bunch of blue box Federal .308 Power Shock ammo based on the stellar reviews I found all over the internet plus it was on sale for a phenomenal price of less than .70c a round. Bought both 150 grain and 180 grain loads. Was utterly astonished how well both the 150 grain and 180 grain loads shot. Both under 2" at 300 yards one ragged hole groups at 100 yards. Even more surprising was both the 150 and 180 grain shot to the same POI at 100 and 200 yards and still close enough at 300 to not be worth adjusting the scope.
Was intending to use the rifle as an economical way to teach myself long range shooting VS using any of my belted or short mag rifles.
Earlier this year after a 3 year + search finally found a suitable good enough scope that matched 90%+ of my long range requirements at a price I could afford and bought it. Ended up buying from a member here a Trijicon Credo HX 2.5-15x42.
Mounted it on a Precision hard Core gear 20 MOA base with Warne horizontally split rings that I glass bed the bottom half of the rings.
Was down to my last 30 rounds each of 180 grain and 150 grain Federal PS ammo and was done mounting the scope so I was really itching to sight in the scope and get started shooting long range, and I had finally acquired my 308 dies but hadn't done any reloading so I stopped by my local Cabela's and surprisingly enough they had the same Federal power Shock ammo but only in 180 grain so I bought two boxes.
Three days later was at the range and after setting my scope up for eye relief and getting the cross hair vertically plumb to the barrel, started my zeroing process. As I wanted to save the Federal PS factory ammo I knew to be vary accurate, I instead used the newly bought 180 grain ammo to zero my scope.
From the very first round I loaded by hand into the chamber I noticed closing the bolt required more force than should be necessary based on shooting the other ammo. I ejected the round and then chambered a round from the other ammo that shot so well. It took undoubtedly noticeably less force to close the bolt and chamber a round with the odder ammo VS the new ammo.
Not a significant more amount but definitely noticeably more.
I used the older factory ammo and once the rifle was zeroed at 100, shot one 5 shot 100 yard group and it was true to past performance a single ragged hole group. Shot three shots of the more difficult ammo and it produced a group just over 2" C-C. Bolt didn't get any more difficult to open or close and didn't notice any increase in felt recoil.
I chose not to shoot any more of either ammo until I got home and checked the ammo.
Now this is where I get totally baffled. Using my Hornady Head Space comparator and bullet comparators I measured the loaded case lengths from base to shoulder and from base to bullet Ogive. Measure 10 different cases each of the older 150 grain and 50% of the new 180 grain ammo and here is the measurements averages I came up with:
Older 150 grain Federal Power Shock ammo:
Base to Shoulder measured 1.6185" +/- 0.0015" for ten randomly selected cartridges of the 18 left
Base to Ogive measured 2.150 +/- 0.002" for same ten randomly selected cartridges
Base to tip of bullet 2.7185 =/- 0.0155" same cartridges I understand this measurement tends to be unreliable due to significant variances in bullet length but I measured it anyhow.
New a180 grain ammo that was difficult to close bolt on measured 50% of all remaining ammo
Base to shoulder 1.6180 +/- 0.0018"
Base to Ogive 2.1225 +/- 0.0020"
Base to tip 2.7035 +/- 0.0191"
Yes you read correctly the rounds that were more difficult to close the bolt on were the essentially the same length base to shoulder and were SHORTER in the two other measurements I made. I measured every round five times each for every measurement and did an average.
All measurement are shorter all SAMMI maximum.
I then used a dry erase marker and coated the entire exterior of both different loaded casing and chambered them and noticed no significant makings on the ejected rounds. I also measured fired casings of both different loadings and again both were well below maximum SAMMI specs.
So how can Factory loaded ammo that is the essentially the same length from base to shoulder and shorter from base to Ogive AND shorter than SAMMI maximum both loaded and fired be more difficult to chamber than a round essentially longer or the same length?
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