Light loads causing difficult to open bolt? First time out with Ross 1905E

[uscra112]

The .303 is a rimmed cartridge. Drilling flash holes out was a fix for shoulder setback in rimless cartridges.

[WILCO]

[uscra112]

You got it.

[WILCO]

The .303 is a rimmed cartridge. Drilling flash holes out was a fix for shoulder setback in rimless cartridges.

For the record, I didn't catch that fact until it was pointed out.
Love learning and relearning.

[swheeler]

Neck sizing should cure this problem for you, a Lee collet neck sizer sounds to order. Even though this is a rimmed cartridge that is supposed to head space off the rim the chambers are large sized for extreme field conditions. Neck sizing will make you brass last longer by a large margin and allow you to head space off the shoulder like a rimless cartridge. As ShooterAz suggests drilling flash holes will help keep the shoulder where it should be.

This was posted by me before uscra112 ever rang in- THIS IS POST #8 in this thread

It has been common knowledge of handloaders for many many years that headspacing off the shoulder on RIMMED and BELTED cases promotes case life, accuracy. If you push the shoulder back say .020"(not that far out of liner with some full length dies)every time you FL size to load and the rimmed cartridge alread has .010" headspace, if you have enough pressure to expand the case from shoulder to bolt face- you have stretched that brass .030" it will soon seperate.

[uscra112]

*sigh* This has nothing to do with his apparent case-sticking problem.

[swheeler]

for the record, i didn't catch that fact until it was pointed out.
Love learning and relearning.

Read post #8! POSTED THE DAY BEFORE uscra112 even posted. I mean who can look at a big picture of case head stamped 303 BRITISH and say I didn't realize it was a rimmed case

[swheeler]

*sigh* This has nothing to do with his apparent case-sticking problem.

Sigh all you want, I'm not convinced of that. But lets just let the OP try his 5 fire formed cases and then we'll know. I take it you have never loaded for any belted cartridges either, or at least only a couple times before you had to buy new brass same as your 303. If you have a shoulder use it, if not you are stuck with a belt or a rim

[303Guy]

The .303 is a rimmed cartridge. Drilling flash holes out was a fix for shoulder setback in rimless cartridges.

This is true but treat it as one would a rimless. Forget the rim, the case must headspace on the shoulder. With the primer protruding, this is not going to happen and the case is not fully fireformed.

Looking at those primer, that is quite a stout load for a 303 Brit. Don't look at the outer edge of the primer - that only gets squared off when the case sets back or the primers are softer. Look at how the primer has filled the firing pin indent. The problem could be a pressure wave that expands the neck and shoulder area. I have had full pressure loads that fill the firing pin indent as much as these if not more so from a gun with rust pitting in the neck area with not extraction difficulties. The necks do not expand into the (large) pits. Then again I have fired light, shotgun powder loads with light boolits in the same gun that hardly showed any firing pin indent filling at all yet were jammed tight into those neck rust pits!

A little trick on fire forming cases with moderate loads is to lightly lube the cartridges to be fired. This allows the neck and shoulder area to fill out forward while allowing the case body to progressively expand rearward to fully seat against the bolt face without drawing around the web area. Cases fireformed in this way will still have a nominal clearance due to springback. Even cases that are tight on closing will come out freely. With this method one can see how the striations on the case get progressively longer from the shoulder area where there are none, to the web area.

[M-Tecs]

First being rimmed or rimless has zero bearing on the OP's issue of the primer backing out. Shoulder setback is not an issue per the OP and it shouldn't be based on it being a rimmed cartridge. Drilling flash holes is done for a variety of reasons of which shoulder setback in bottleneck case is just one. Wax bullet or blank use is another (been drilling flashholes since 1970 for this). Same for some drilling for better accuracy with Blackpowder (I don't believe after limited testing it but some do put great stock in it).

Headspacing off a rim or belt is the SAAMI standard for belted or rimmed cartridges, however, just like using SAAMI specs for bottleneck cases the SAAMI specs don't maximize case life or accuracy. Regardless if the case is a bottleneck, rimmed or belted case adjusting the sizing die to minimize shoulder setback is optimal.

All primers back out on firing. When the case does not reset the cause is simple. The pressure in the primer pocket is greater than the pressure of the case pushing back. This pressure/movement is normally referred to as bolt thrust.

This is just my opinion but I believe in bottleneck cases faster powders require more pressure to reseat primers. This is solely based on personal experience with light loads in a 30/30. My guess is that the pressure with fast powders the pressure curves between the primer and powder is such the case pressure dissipates before the primer pocket pressure dissipates???????

[swheeler]

303 I used the lightly oiled case trick on the 8x56R with 13. gr red dot to get cases formed-primers to reseated. I don't have neck dies for it so I just size about 3/4 of the neck. The dies Lee provide OVER size this case large amounts. I actually headspace off the shoulder on my 30/40 krag, 8x56R and the 7.62x54R all rimmed cartridges. I also headspace the 264 Win mag, 7mm Rem Mag and 300 Win off the shoulder, 458 uses the belt like it was designed. Thank you for chiming in.

[john.k]

note the headstamp...RP...notorious for cribbing the last microgram of brass by making rims way under spec........Headspace excessive by virtue of brass rim being a lot under spec thickness.........cure ,dont waste your money on Remington Peters ammo,buy PPU .

[swheeler]

note the headstamp...RP...notorious for cribbing the last microgram of brass by making rims way under spec........Headspace excessive by virtue of brass rim being a lot under spec thickness.........cure ,dont waste your money on Remington Peters ammo,buy PPU .

John I just went through my junk can and found some 303 Brit. tiny test sample but here's what I got....

R-P rim thickness .061"
HXP 70 .059"
HXP 71 .059"
VPT 40 .061"

[Multigunner]

Commercial sporting .303 cartridge case rims are within specs. Many Military .303 case rims are out of spec by being too thick.
Military rifles often have headspace on the loose end of maximum allowable headspace.
Older British .303 sporting rifles sometimes can not be used with military surplus .303 cartridges.