300 Win Mag??? Weird Shooting Chrony Master F1 8.8:8.8 reading

[Alberta Wexit]

I had similar issue when first started reloading. Loaded and built a group in January at probably -25F. Shot great. Same load mid summer July frozen bolt. That's when I decided to test all loads in heat. Has never been a concern in cold weather. Don't think I ever missed and animal I could attribute to this. But interesting. Thanks for the information on various powders.

 

[ofbandg]

My shop is in my basement where it's usually pretty cool and the bench at the range is full in the sun where it can be really hot. Once, when I was working up a load with my 30-06 AI and Superformance, I was being careful to wait between shots to let my rifle cool down, and I noticed after ten shots that the velocities were increasing gradually as I shot. In the course of half and hour I had gained almost 90 fps. I'm not that surprised because for many years Rel 22 was my favourite powder in many calibers and it's very changeable but that is the first time I ever got to watch it happen. Nowadays I always make up enough ammo to check my load regularly during hunting season to see if it is shooting where it should - even with powders that are supposed to be stable.

 

[bluedog69]

Your handloads with a 180 should be going 3000-3100 easy. I shoot 215s at 3000 in my win.

Keep adding powder till you reach pressure. Also that's not good if you haven't found the lands, try a longer bullet just to see where they are

I may have to borrow some longer bullets from a "300 RUM nut" that I know. He had a pile of different bullets. I only have the 180's for my 30/06 and 125's for a kid load in the 30/06.
Not sure what good finding the lands will do for me though. I know that my buddy that owns this 300 win mag will want them to fit in the magazine.

 

[bigpapa]

Hello good people, hope all are well. May have said this once before if so this is a remind, if you move a rifle, pistol , camera or what ever from hot to cold or cold to hot without a cool down or warm up, the inside of all the objects spoke of here will sweat and at times a lot of moisture could affect a lot.

 

[JustMe2]

Most will agree that 80F seems to be the temp that powders start having extreme pressure spikes. During temps that are nearing or exceeding that 80F mark, I put my ammo in a cooler with one cold pack (with my lunch LOL). It keeps the ammo cool, but not frozen. I also do not put my box of ammo in the hot sun on the bench. It stays in the cooler until ready to shoot. Some times, I carry a second single-six-pack size cooler with a hand towel, ice, and water to cool my barrel.

 

[bluedog69]

This was a kinda mild load around 3000fps with a 180gr Sierra Boat Tail but it shot really well.View attachment 279718

Your handloads with a 180 should be going 3000-3100 easy. I shoot 215s at 3000 in my win.

Keep adding powder till you reach pressure. Also that's not good if you haven't found the lands, try a longer bullet just to see where they are

Well I switched and tried 71 gr of IMR 4350. Got an awesome 3" 4 shot group at 100. Hahahaha. These chronoed 3009, 3039, 3033, 3026.

I did find the lands but it won't do any good. I found it with a 180, 210, and 225. The magazine allows about 3.410 length max. Jam length is about 3.502 with the 180. Been trying to not bump the shoulder on the reloads. They still chamber easy. I think I will try to full length size them and try again.

This is not looking good for this rifle.

 

[baldhunter]

If your getting 3" groups at a 100yds you probably have issues other than just the load.My guess you might have bedding issues.Next time you go to the range,fold some sheets of paper and slide it under the barrel all the way the full length of the barrel channel and see if the groups improve.Stocks can often can cause poor accuracy issues.Heavy triggers can too.Eliminate any stock issues and get the trigger down to around 2.5-2.75lbs and most rifles will shoot fairly well and not nearly as picky with the loads either.

 

[Mike Matteson]

I have only seen on rifle that wanted forearm pressure. I would float the barrel from where the barrels meets the action to the end of the stock, so you run a business card between the barrel and stock. The other is you need to bed the action in the stock. As said by baldhunter have the trigger worked on or replaced. Personally I like under a 1lbs or there about, but that personal. It would be better to have a gunsmith set this up. I take it you are not very skilled in working on rifles, which isn't a bad thing, but I feel it would be saver for you and other around you. Get a torque wrench in inches pounds. Most larger sporting good store should have them. It all learning curve, and we are all learning.
Unless something is really wrong with that rifle, (300WM) there shouldn't be a problem of getting to 1/2" ground @ 100 yds. It's sound like some TLC is needed.

 

[Rosebud]

So just took a few shots with buddies 300 Win Mag. Factory Winchester 180's
gave about a 3010 average. (2 shots 3001 and 3022)

My handloads with Sierra 180 SBT gamekings, 72 gr of H4831, CCI LRM primer, COL 3.360 to fit in Mag(NEVER found lands even with bullet barely in case) gave a
readings of 2752, 2732, 2756 and 2798.

Shots were in this order 2752, 2732, 2756 handloads
then 2 factories 3001, 3022,
then handload 2798.

It is 90 degrees out and we were in the sun. Took gun and shells out of AC house and shot off deck.

QUESTION 1) Will this extreme heat(sun) raise FPS as the gun and shells get warmed up in the sun?

QUESTION 2) The last two shots 3022 factory and 2798 hand load the chrony screen displayed 8.8:8.8.
I shut it off and just for a split second it said 3022 then shut off? Then I took the handload
shot and 8.8:8.8 again. Shut it off and it read 2798 for about 1 second then shut off?
Anyone ever seen this displayed? 8.8:8.8? Chrony in sun getting too hot? All I have ever seen
in low light is err1 and err2 readings.


So far I am not very happy. 2" four shot factory ammo group and the same with my handloads. This is a new
TC Venture with a 4-16x44 Diamond back tacticial FFP Vortex. Gonna try cleaning it good.

QUESTION 3) Should I jump to 73 gr of H4831? No pressure signs, no sticky bolt lift etc. Was kind shocked to see
2750 ish on handloads and 3010 ish on factory El Cheepo Win ammo. 270 FPS difference on first 3 handloads and factory shots.

Any suggestions?

I'll attempt questioning#2 ,does it have a fresh battery. Sun shades, are you shooting late in the afternoon.

 

[bluedog69]

I have only seen on rifle that wanted forearm pressure. I would float the barrel from where the barrels meets the action to the end of the stock, so you run a business card between the barrel and stock. The other is you need to bed the action in the stock. As said by baldhunter have the trigger worked on or replaced. Personally I like under a 1lbs or there about, but that personal. It would be better to have a gunsmith set this up. I take it you are not very skilled in working on rifles, which isn't a bad thing, but I feel it would be saver for you and other around you. Get a torque wrench in inches pounds. Most larger sporting good store should have them. It all learning curve, and we are all learning.
Unless something is really wrong with that rifle, (300WM) there shouldn't be a problem of getting to 1/2" ground @ 100 yds. It's sound like some TLC is needed.

I have glass bedded a muzzle loader myself and know that it made it go from worthless to pretty decent. I have also free floated some wood stocks too.
Since this is a friends rifle I really don't want to start a lot of time consuming work myself on it.
I will probably just have to look it over good and see what I think about glass bedding it for him. Also need to talk to him about it.
I also want to try this new box of 180 SIE SBT in my 30-06 to eliminate them as a variable.
So much for an "easy" sure I can tighten your groups up no problem with hand loads.

 

[bluedog69]

I'll attempt questioning#2 ,does it have a fresh battery. Sun shades, are you shooting late in the afternoon.

I used it today as it was cloudy and only about 85 degrees. Never missed a beat. My boys and I shot a 17 hornet, 22 hornet, 30-06,7 mag and the 300 win through it.
My guess is that the extreme heat was getting to the display the other day when it acted strange.
Yes I always run the sun shade on it. I also know how it quits reading as it loses light.
I have had this one for about 24? Years.

 

[Rosebud]

I used it today as it was cloudy and only about 85 degrees. Never missed a beat. My boys and I shot a 17 hornet, 22 hornet, 30-06,7 mag and the 300 win through it.
My guess is that the extreme heat was getting to the display the other day when it acted strange.
Yes I always run the sun shade on it. I also know how it quits reading as it loses light.
I have had this one for about 24? Years.

Well, you have that covered. I'll let others give advice on the rest. Good luck. One more thing, your shooting a 300 win mag , where you close enough to get muzzle blast. Seen them act strange from that.

 

[baldhunter]

This guy had accuracy problems with his TC Venture.See the video on how he fixed his problem.

 

[bluedog69]

Well, you have that covered. I'll let others give advice on the rest. Good luck. One more thing, your shooting a 300 win mag , where you close enough to get muzzle blast. Seen them act strange from that.

Nope I had it sitting about 15 feet out in front of the muzzle. This one has the readout in a little box that is on a 15 foot telephone cord.
Just for the muzzle blast problem.

Thanks again.