texhookem

The most accurate factory load I ever shot out of my rifle(30-06) was a winchester supreme 180 grain accubond, now I want to load 150 grain ballistic tips. I measured the length of a leftover winchester supreme 180 grain accubond and seated the 150 grain ballistic tips to make a cartridge the same length as the winchester supreme accubond. I am wondering if that is a good idea or not. I am thinking that the 150 grain bullet might be seated a little to far out. I have heard about different methods to see what the proper seating depth is for your gun. I would really appreciate anyone who could give me suggestions on what to do. Thanks.

texhookem

also what would be a good way to see if your bullet is touching the lands

texhookem

what i typed may be difficult to understand but my basic question is that if my gun shoots a 180 grain bullet very accuratly but i want to use 150 grain, should i seat a 150 grain bullet to make a cartridge the same length as a cartridge with a 180 grain bullet

stubblejumper

The most accurate bullet seating depth in a particular gun will vary from bullet to bullet.The only way to determine the most accurate overall length in your rifle is by trial and error.Most factory loads are actually loaded quite short to ensure that they fit in the magazines of all guns that the cartridge is chambered for.I find that the most accurate overall cartridge length in most guns is longer than that of factory loads.

texhookem

the winchester 180 grain accubond is actually loaded longer than most ive seen(3.3 inches), which is why i loaded my bt's to that exact length just to start out with and then adjust from there. i was just worried that the 150 grain bullet may not be seated deep enough.

texhookem

there is at lease one distance of the caliber (.308 inches) of the bullet inside the case. Is it a good rule of thumb to go by one distance of the caliber as a minimum seating depth.

stubblejumper

One caliber of the bullet in contact with the neck is fine.Be aware to in the case of boattails you have to seat them deep enough to maintain the same amount of contact while allowing for the boattail.

jmfa1957

I have done this in the past:

Seat a bullet into your case far enough out so that it is guaranteed to touch the rifling. Use the bolt to force it in. Extract this case and measure it with a caliper. It is not, in my opinion, a good idea to use a loaded cartridge to do this; use an empty, unprimed case to do this.

Start backing the bullet a bit away from the rifling by seating your bullet deeper in 0.010" increments. You should make several rounds up at different seating depths and see which depth gives the best accuracy. Often, but not always, the closer the bullet is to the rifling, the better the accuracy. I found that about .010" to .020" from the rifling is best in my .30-06.

If you make ammunition where the bullet touches the rifling, be EXTREMELY careful to back your pawder charge away from the maximum in your loading manual. The pressure buildup in a maximum charge with the bullet touching the rilfing can be very dangerous. Look out for signs of excessive pressured, described in your loading manual. If you see cratering around your primer, if the bolt is "sticky" after firing, if extraction is difficult, you are in a dangerous pressure regime. Cease firing that ammo immediately, and use a bullet puller to remove the bullet & powder so you can start over.

Good luck, and have fun!

handloader1

Invest in a Stoney Point O.A.L. Gauge, Modified Case (for your particular cartridge), Comparator and indivudual insert (for your particular caliber). Go to www.stoneypoint.com Good luck.

HighDesertWolf

I would never seat another type bullet based on the COL of another. because even if the COL from tip to base is the same, its not the tip that contacts the rifiling obviously its where the ogive begins into the full diameter of the bullet and that can vary a ton between two types of bullets especially of different grain weights also COL can vary for different charge weights and powders. I would go about it how jmfa1957 explained it, I deffinately recommend getting the stoney point OAL gauge aswell. In my 308 win load I use a 165 grain Sierra BTHP gameking with a charge of 45 grains varget to stay with in SAAMI specs the maximum overall length for my charge is 2.800 and my minimum is 2.750, I tried seating my bullet so that it would be .030 from the lands and worked it untill I was .010 from the lands. With no difference in accuracy between .030 and .010 but only getting 1.25 inch groups at 100 yards with a rifle that shot .5 inch with remington express 150 grain core lokts I was very frustrated, then I decided to seat my bullets at 2.750 and work up to 2.800 at 2.750 my groups shrunk to .75 inch then I moved up to 2.760 and my groups openned back up to an inch so i backed it off to 2.755 and i was shooting less then .5 inch groups at 100 yards. Basically im trying to say is it isnt always the best to seat your bullets close to the lands. when seating your bullets to the ideal COL what you are doing is timing the bullet just right for the load so that the bullet seats square into the lands though it is very logical to decrease the gap between the lands and the bullet to insure a sqaure fit of the bullet into the bore it doesnt always work.