Lee Enfield Head Space

[Kerryjack]

Hi, I'm new to this forum so please cut me some slack if I botch things.
I want to purchase a #4 Lee Enfield so I can compete in BAM events, F just isn't doing it for me any more.
Most things are common sense but I am getting tripped up on the head space thing with selecting a suitable rifle.
The HS tolerance is clearly specified in the manufacturer's documentation yet the head space is being touted as a critical issue with purchasing this rifle.
I have spent hours on forums and reading various opinions, some from asserted experts and yet there is no clear winner or technical consensus.
One of my main concerns is that many of the opinions claim that the HS, even if within the manufacturer's specification, can have a devastating effect on the accuracy of the rifle. Others say bunkum to this assertion.
I spoke with a ballistics smithy from Texas who just happens to be one of my clients and while he does have a very firm opinion on this issue, he suggested I put this question to a forum, such as this, and ask if anyone is willing or able to give a technical reason for the assertion that HS affects the accuracy of the #4 Lee Enfield.
So, why is head space seen as such an issue when purchasing this rifle even if it is within manufacturer's spec?
Thanks
-KJ

[bladeracer]

Hi, I'm new to this forum so please cut me some slack if I botch things.
I want to purchase a #4 Lee Enfield so I can compete in BAM events, F just isn't doing it for me any more.
Most things are common sense but I am getting tripped up on the head space thing with selecting a suitable rifle.
The HS tolerance is clearly specified in the manufacturer's documentation yet the head space is being touted as a critical issue with purchasing this rifle.
I have spent hours on forums and reading various opinions, some from asserted experts and yet there is no clear winner or technical consensus.
One of my main concerns is that many of the opinions claim that the HS, even if within the manufacturer's specification, can have a devastating effect on the accuracy of the rifle. Others say bunkum to this assertion.
I spoke with a ballistics smithy from Texas who just happens to be one of my clients and while he does have a very firm opinion on this issue, he suggested I put this question to a forum, such as this, and ask if anyone is willing or able to give a technical reason for the assertion that HS affects the accuracy of the #4 Lee Enfield.
So, why is head space seen as such an issue when purchasing this rifle even if it is within manufacturer's spec?
Thanks
-KJ

If you're loading your own ammo then headspace becomes irrelevant, size your brass to fit your chamber with whatever headspace it has currently.

[bigrich]

Hi, I'm new to this forum so please cut me some slack if I botch things.
I want to purchase a #4 Lee Enfield so I can compete in BAM events, F just isn't doing it for me any more.
Most things are common sense but I am getting tripped up on the head space thing with selecting a suitable rifle.
The HS tolerance is clearly specified in the manufacturer's documentation yet the head space is being touted as a critical issue with purchasing this rifle.
I have spent hours on forums and reading various opinions, some from asserted experts and yet there is no clear winner or technical consensus.
One of my main concerns is that many of the opinions claim that the HS, even if within the manufacturer's specification, can have a devastating effect on the accuracy of the rifle. Others say bunkum to this assertion.
I spoke with a ballistics smithy from Texas who just happens to be one of my clients and while he does have a very firm opinion on this issue, he suggested I put this question to a forum, such as this, and ask if anyone is willing or able to give a technical reason for the assertion that HS affects the accuracy of the #4 Lee Enfield.
So, why is head space seen as such an issue when purchasing this rifle even if it is within manufacturer's spec?
Thanks
-KJ

Because 303 is a rimmed round , it head spaces on the rim. With rimless rounds they headspace on the case shoulders. So if the headspace is on the loose side with a rimmed round, it won’t compress the rim enough to give consistent accuracy. Least that’s my understanding of things