Help, confused IMR 4350 & 300 win mag

[HighKnob]

Need help, I'm confused with some info i have. My old horndy manual list's 300 win mag 71 - 79 grains of IMR 4350 for a 150 grain bullet. Top velosity was 3400 fps. I had started on a new rifle and load. Shot some single rounds of the low charges and started loading 3 each starting at 75.5 grains. I didn't show any pressure at 75 grains so i moved to 75.5. Hadn't set up the chronmagraph until then. That set of 3 averaged 3400 @ .043 inches 100 yds. I had 3 more loads at 76.5, 77.5, 78.5 but was afraid to shoot them. It didn't show hardly any pressure up to 75.5 but just a bit of shin on the base. No sticky bolt or hard to open or flat primers. When I got home and got to checking I couldn't find any where that list above 74 grains for that load. What's going on? I've loaded from this manual for a lot of years and never had a problem.

 

[HighKnob]

Nobody??

 

[Shortmagman]

I just looked at the Hodgdon web site and they give loads for two 150 grain bullets using IMR-4350, and I found it to be interesting. With Barnes 150 TTSX the max load is 75.0 grains of IMR-4350 for 3347 ft/sec.. With another 150 grain bullet the max load is listed as 74.0 for a velocity of 3254, so I think you are at or above the max load for a 150 grain bullet.

I have a Hodgdon manual that is close to 20 years old, the data listed for the 7mm Rem Mag, H1000 and 175 grains Hornady bullet shows the starting load above the max load that Hodgdon now lists for this combination. Why?

Is the new data more accurate? Did the burn rate for H1000 change in the last 15 years?

What does this prove? I think it proves that we must look at more that one source for loading information. Thing do change.

 

[kcebcj]

Just checked the Nosler load data using IMR 4350 and the 150gr Accubond max is 74gr @ 3420. I think your there! Be careful.

 

[HighKnob]

Thanks, that's what I thought, but haven't been back to the range since. Guess it will be next week. Loaded a few more near 75.5 to try.

 

[Bart B]

I didn't show any pressure at 75 grains so i moved to 75.5. Hadn't set up the chronmagraph until then. That set of 3 averaged 3400 @ .043 inches 100 yds.

OK, so much for powder charges.

I wanna know more about those three groups that averaged less than 1/20th MOA; about 1/23rd of an inch!!!!!

 

[Mikecr]

What's going on?
Different barrel, different lot of powder, and no problems with your tested results.

Is there some concern?

 

[HighKnob]

Sorry, typing error. Supposed to be 0.43 inches.

 

[HighKnob]

Mikecr, this was all new to me stuff, first trip to the range. Still not sure other than the manual was just printed wrong for that powder. Got some more loaded but haven't had time for a range trip yet.

 

[backwoods83]

I'm not telling you to do anything stupid, but max charge is obviously different for every rifle, seating depth, primer type, brass make, bullet etc... I have used 76.5grns of Imr4350 under a 178 hornady bthp touching the lands using winchester brass, CCI BR2s and a OAL of 3.531", I didn't go into an over pressure issue. Get data from 2 or 3 manuals to get a starting point, work up slowly, and find the max for "your" combo, not the books max. Be safe.

 

[HighKnob]

Thanks for the replies. I'll keep working on it, now if i can just get some range time.

 

[Bart B]

Get data from 2 or 3 manuals to get a starting point, work up slowly, and find the max for "your" combo, not the books max. Be safe.

If the max charge is supposed to be at SAAMI max average specs of 52,000 CUP, how does one measure their charge's pressure without a pressure measuring system to find out what their load produces in their barrel?

I don't know of any visible inspection or physical measurement methods of fired cases is a way of assesing max pressure that's accurate.

 

[backwoods83]

No Bart there is not an exact method without a pressure barrel, however there must be some logic behind your smartass replys to everyone. I don't care who says what to me so, that said you're a ***, and no one is as wise as you. Since you're so **** good maybe you should check into working for Hodgdons, Sierra, Berger, etc... they need someone of your genius.

 

[Bart B]

No Bart there is not an exact method without a pressure barrel, . . .

Wrong.

RSI - PressureTrace

It uses your barrel; no pressure test barrel needed.

How's this for a "smart ***" response to your statement based on ignorance?