Determining seating depht for a hunting rifle

[boomer79]

I have a standard Remington 700 Sendero 300 RUM. When I measure the overall seating depth for a 180gr. Nosler ballistic tip it is 3.788. Of course, to fit in the magazine it must be no greater than 3.60. Hypothetically, if I can find an accurate seating depth that is 3.700 am I wasting my time for a hunting rifle when the next round must be 3.600 or less?

 

[300WSM]

Oh my...been down this road a million times with many customers.

With the hunting rifle, whatever you have that can easily fit into the magazine is gonna be your cap. Unless you want to make it a single shot.

If all you can go is 3.600 then make that your max cap number and play around there. 3.550 up to 3.600 this is for hunting and you are going to want to have those three rounds.

having said that, I firmly believe that you will be able to find a load that will net you sub 1" groups all day long 3.600 or under. Again, it is a hunting rifle. RIGHT?

Furthermore I don't understand what you mean with the seating depth of a ballistic tip to be 3.788

How are you measuring this? Are you saying that your chamber dimensions are 3.788 with a ballistic tip?

If that is the case I have to question that because then at that point you are saying that your chamber can handle a Max OAL of .188 longer than SAAAMI. That would be a rather unusually large number over saami. The norm is .050 to .075...but nearly .200??? Really?

 

[Guy Miner]

Remington does make some really long chambers - even 20 years ago. Still, they typically shoot real well.

Boomer - I'd try 'em at 3.6" and suspect that they will work out just fine. Nosler and Sierra bullets tend to tolerate a "jump" to the rifling quite well.

If you want to mess around with longer-than-magazine-length rounds for maximum accuracy, just remember that your rifle will be a single-shot proposition. That doesn't bother me in the least, as I have often hunted with muzzle loaders and sometimes with a single shot Ruger.

Regards, Guy

 

[jmad_81]

Yep, load them at the 3.600 and see what happens. You can work back from there. A single shot bolt gun for hunting doesn't make much sence.

 

[RiverRider]

What they said...you don't always have to be up next to the lands to get accuracy.

 

[Guest]

I own very few rifles which shoot best out close to the lands. A couple (my 'bees) have sufficient throat length to make it impossible to seat out near the lands. My theory on seating is simple. I measure throat length and magazine length, and start at the shorter of the two (longest COL that will reliably feed and chamber) and work back from there. I have only found one rifle in my lifetime for which I couldn't find an accurate load - and that POS Remmy went to a gunsmith who wanted the action for a project. I bumped into him last week and he explained that the reason that gun wouldn't shoot was that the action, barrel, and threads were all in three different planes, from an alignment standpoint. He ended up recutting the threads to sit square, and barreling it in a .338 wildcat he was working on based on the 375Ruger case. His wife drug him off after a few minutes so I didn't get as much info as I'd like.

Bottom line is, you can find an accuracy node within your mag box limits, I suspect. It'll just take some doing.

 

[DrMike]

Bottom line is, you can find an accuracy node within your mag box limits, I suspect. It'll just take some doing.

+1

 

[RiverRider]

I'd suggest using a comparator in order to facilitate repeatability.

 

[300WSM]

The most important question was never asked to you here and I am guilty as well because my first reply I never asked it either... :lol:


What grouping/accuracy are you seeking? What would be satisfactory?

Is 1" and a little better good enough? I promise you with no trouble whatsoever this can be obtained at 3.600 or even shorter. Unless your bbl has no rifling you can get this no problem.


P.S.
Boomer,
Please know that I'm not doubting your ability determining the length but I still question that distance.

I echo again that most chambers have .050 over SAAMI max and around there is the normal...sometimes up to .075 ....BUT your getting nearly .200 over?
Even if the chamber is a bit big.... .200 over? I still shake my head on that number.

 

[OU812]

When I start to develop a load I am first concerned with 3 things. 1 will it fit my mag box, 2 will it feed properly and 3 will it chamber. If yes to all 3 then I'm off to the races.

Of all the hunting rifles I've owned I have had zero issues getting very accurate loads developed using the mag box length as my starting point and most often don't even have to seat the bullet deeper.

I can honestly say I have never measure the distance to the lands (other than fire forming). I do not desire a single shot bolt action hunting rifle so as long as they fit as listed above I don't care what the distance to the lands is. Just my .02


Bill

 

[Richracer1]

On all my RUMs, I have all four, the max I can go and fit in the magazine is 3.670" and still feed reliably. Now, I have not had any of my RUMs like anything that long. When starting to develop loads for the RUMS, I'll go to 3.600 find what powder charge will give the best group and then start working the seating depth to further tighten the group.

Here's my what I have for OALs for my 300RUM (measured the crude way, bullet tip to brass base):
180AB & 200AB - 3.635"

My other RUMs for comparison:
7mm - 150ET at 3.655 and the 160AB at 3.635

338 - 200ET is 3.620, 225AB is 3.640, 225TSX is 3.625, and the 250AB is 3.640

375 - 260AB is 3.630, 270TSX is 3.610, and the 300AB is 3.630

Here's some targets:
7mm -
150ET


160AB


300 - 200AB:


338 -
200ET


225AB


250AB


375
260AB


300AB

 

[boomer79]

Thanks, Very helpful. I will start at 3.600 with the most accurate load and slight modify both deeper and longer. The magazine will load predictably at 3.650 if needed.