Velocity -374fps different than book?

[Spitzer]

I've been working up a load for my 243win 80gr. GMX to MAX book listed (hodgdon) load of 38.5gr. Varget for a velocity of 3355fps. When I chronied them today the velocity was only 2981fps. What gives? I've rechecked everything and can't figure it out. I've been reloading a long time never had this much difference.

Should I keep going up in charge weight, or switch to IMR 4350? or H4350?

 

[coyote]

Some higher bc bullets have a short bullet shank area causing less pressure to build up .
How do your primers look for flatness if there is still a rounded edge go up with the powder, also check for ejector marks and bolt lift.

I just built a 6mm slr it has the same case capacity as a 243 and with berger 105 vld's the hodgdon data showed a max load of about 40gr H4831 I am loading 45gr with no pressure signs.

 

[H4831]

Some higher bc bullets have a short bullet shank area causing less pressure to build up .
How do your primers look for flatness if there is still a rounded edge go up with the powder, also check for ejector marks and bolt lift.

I just built a 6mm slr it has the same case capacity as a 243 and with berger 105 vld's the hodgdon data showed a max load of about 40gr H4831 I am loading 45gr with no pressure signs.

I deleted my post, because I quoted the wrong writer. Will try again, with other poster.
Actually, my reply is fitting to both Coyote and Spitzer so doesn't matter much.

 

[H4831]

I've been working up a load for my 243win 80gr. GMX to MAX book listed (hodgdon) load of 38.5gr. Varget for a velocity of 3355fps. When I chronied them today the velocity was only 2981fps. What gives? I've rechecked everything and can't figure it out. I've been reloading a long time never had this much difference.

Should I keep going up in charge weight, or switch to IMR 4350? or H4350?

This is interesting. I too, am working for an accurate load for my new 243. Mine is a bit too slow a twist for 100 grain, so am going to settle for 75 grain hollow point, which seems to have good potential for accuracy. I have never used Varget, but after reading so many good reports on it, I today, just bought my first can of Varget.
Of course, the old loading charts, or my records, don't include Varget, so I look at the modern Hodgdon chart and see, I think it is, 41, or thereabouts, for the 75 grain bullet.
Judging by your results, that will be much too slow to bring out the accuracy potential of my 75 grain hollow point. Worse, I don't have a chronograph now.
Maybe you could PM me on your further tests. I'm only about 75 miles west of the Selkirks.

 

[H4831]

I've been working up a load for my 243win 80gr. GMX to MAX book listed (hodgdon) load of 38.5gr. Varget for a velocity of 3355fps. When I chronied them today the velocity was only 2981fps. What gives? I've rechecked everything and can't figure it out. I've been reloading a long time never had this much difference.

Should I keep going up in charge weight, or switch to IMR 4350? or H4350?

Welcome to the world of modern loading books.
In the 1964-65 Ellwood Epps catalogue is a Hodgdon loading chart. In the 243 Winchester, 100 grain bullet, they show 46 grains of H4831, for a muzzle velocity of 3009.
When I had a Ruger 77 243 I worked up to 47 grains of H4831 and, with a good Oehler 33 chronograph, I got just over 3000 fps. There was no sign of excess pressure in my rifle and I had long case life.
Also, bear in mind that this was with the old, original war surplus H4831. Later, when Hodgdon came out with their new H4831, I tested it on a comparison basis with the old powder. I found that full power loading, 60 grains with 130 grain bullet in my 270 Sako, the old powder turned up just over 100 fps higher average, than did the new H4831.
The old Hodgdon chart I am looking at, shows 45 grains of the old H4831 with a 105 grain bullet.

 

[kman300]

I get 3150fps with 45gr H4350 and the 80gr ttsx in a 20" youth model 700. Barnes says 45.5gr H4350 should give 3398fps with the 80gr ttsx but in a 24" barrel. So I'm getting 250 fps less with 4" less barrel and .5gr less powder. How long is your barrel?

 

[Spitzer]

Good point! It's a Rem m700 youth 20" bbl, I forgot to consider this. I guess the book uses 24" bbl, so with a 20" bbl should give 200fps less with same load. Then there's only 174fps difference.

No real signs of real flattened out primer, there is minor shine of an ejector mark on one.

I get 3150fps with 45gr H4350 and the 80gr ttsx in a 20" youth model 700. Barnes says 45.5gr H4350 should give 3398fps with the 80gr ttsx but in a 24" barrel. So I'm getting 250 fps less with 4" less barrel and .5gr less powder. How long is your barrel?

 

[teenahlake]

what kind of freebore have you got, how many rounds thru the bbl prior. Guns for the most parts are individuals, most of us like steak, the occasional bad hunter likes a salad