Help me not be dumb, 77 TMK, H4895

[Marbles]

So, my Tikka is off getting cut and having its action Cerakoted, my reloading stuff has all arrived, and I'm home sick with the flu.

I have Starline 5.56 brass
Federal 205 primers
77 gr TMKs
H4895 and N135

I'm tempted to try loading a few, but I should probably wait until I get the action back and can check seating depth and brass fitment with a dummy load.

I could seat the bullet deeper if it was needed, but if the brass needs to be resized, I cannot safely deprime it.

But, shouldn't new brass fit? I guess I could check it in my AR and if it fits, then worse case I go shoot the AR.

Am I missing something?

 

[rcook10]

Just wait. You can just pull your depriming pin out of the dies or run the neck sizing mandrel high so it cant contact the primer if you really feel the need to resize your new brass if its primed. I usually size/neck bushing most brass regardless of whether it is new except for lapua before loading. I would just wait so you know what your seating depth needs to be unless you already measured your chamber/jump.

 

[DiabeticKripple]

I have punched out live primers in the past. Just don’t ram the decapping pin into it. You can reuse the primers too

 

[SamsonMan22]

Full length size the new brass and seat the bullets to factory mag length.

 

[BigNate]

It seems you have little experience and as such I'd recommend starting out following the reloading manual recommendations for sizing and coal for that bullet.
Trying to make tight fitting cases and guessing at seating depth can lead to head space issues and excessive pressures pretty quick. Magnifying the possibility by not having the gun to check your work.

Just be patient. Take things one step at a time.

 

[xsn10s]

I don't FL resize new brass, it's usually not needed. I've personally never seen a new case that needed FL resize. I do a partial resize on new brass to make sure the case mouths are all concentric and dent free from shipping. I then do a VLD chamber and debur ALL the case mouths. If you have a flash hole debur then this is a good time to use it. Without knowing the chamber/ throat dimensions I'd just wait to make dummies or loaded ammo.

 

[wind gypsy]

If you're using the factory tikka magazine you should have zero seating depth concerns. Seat them to mag length.
Same with Brass. I'd be shocked if you had any issues with virgin brass fitting.
Only thing i'd be worried about is putting too much powder in the reportedly smaller case capacity starline brass such that you're over pressure and need to pull them down. If you go with modest powder charges, I'd not be concerned about loading a handful.

 

[Vern400]

If you've got a standard chamber generally you don't have any trouble with the brass fitting even if you don't resize new stuff. You could load a handful and leave them LONG. You can do the final bullet seating when you get the gun back.

Don't try to get close to maglength. I found better accuracy moving bullets 0.040 inch than 0.004 inch because of the stick - slip coefficient of friction as it relates to the rigidity of the press. Once the bullet starts moving, it moves easier. On occasion I've had them go a little too deep if I was making tiny adjustments.

Brass prep uses more time than anything else. Remove the flash hole burrs, trim the length, and ID /OD chamfer unless it's really good brass like Lapua and they usually don't have any flash old burrs because it's a drilled hole.

 

[PlumberED]

I’m a little late to the party. I dislike brass prep. So, with my latest batch of Starline brass all I did was chamfer the ID/OD of the brass and reload. I had to load the TMK to mag length to get them to cycle through my AR & Howa Mini action. What did you end up doing with yours?

 

[Marbles]

I’m a little late to the party. I dislike brass prep. So, with my latest batch of Starline brass all I did was chamfer the ID/OD of the brass and reload. I had to load the TMK to mag length to get them to cycle through my AR & Howa Mini action. What did you end up doing with yours?

About the same. Chamfered the ID and loaded 30 rounds at 2.26 with a slight role crimp at 0.5 gr under max.

Still waiting to get the gun back, so not going to load more until I can check for pressure. Vihatavuori's load data is based on Lapua brass, so it is possible I'll have to pull the round apart if the Starline has significantly less case capacity. However, given that 5.56 NATO has a spec pressure of 62,366 psi and the load data is for 223 Rem with a. Spec pressure of 55,000 psi I'm pretty confident it will be fine.

I decided to load with the N135 I have on hand to start rather than using the H4895.

 

[PlumberED]

I had good luck with 23.6 H4895, 69 SMK, Starline brass & CCI 41.

 

[TaperPin]

When waiting on a rifle to measure (usually a friends rifle), to save time I’ve put loads together and left them slightly long. Then, once the chamber can be measured it’s just a matter of seating them to the propper depth.

Even if your length is governed by what fits in the magazine, it’s always a good idea to check again with any new bullet. More than one rifle shot great and seemed reliable, but was actually into the lands and extracting a life round pulled the bullet, dumped powder everywhere and disabled the rifle.

 

[Marbles]

When waiting on a rifle to measure (usually a friends rifle), to save time I’ve put loads together and left them slightly long. Then, once the chamber can be measured it’s just a matter of seating them to the propper depth.

Even if your length is governed by what fits in the magazine, it’s always a good idea to check again with any new bullet. More than one rifle shot great and seemed reliable, but was actually into the lands and extracting a life round pulled the bullet, dumped powder everywhere and disabled the rifle.

If USPS does not screw up, I'll have the rifle back Monday and find out if I have to pull bullets. On the 77 TMK, at mag length, the case neck is pretty close to the ogive, so I expect it will be good. However, reality always trumps theory, so we will see.

 

[Marbles]

Got the rifle back today, round loads without contacting the lands, now to shoot and check for pressure.

I did a Woods Metal casting of the chamber today, it appears the throat is formed looser than 223 Rem, but a touch tighter than a 223 Wylde.

 

[Marbles]

And no pressure signs, so I'll load up some more.