a bit different approach

src/game/client/c_baseentity.cpp

@@ -433,6 +433,7 @@ BEGIN_RECV_TABLE_NOBASE(C_BaseEntity, DT_BaseEntity)
 	RecvPropDataTable( "AnimTimeMustBeFirst", 0, 0, &REFERENCE_RECV_TABLE(DT_AnimTimeMustBeFirst) ),
 	RecvPropInt( RECVINFO(m_flSimulationTime), 0, RecvProxy_SimulationTime ),
 	RecvPropInt( RECVINFO( m_ubInterpolationFrame ) ),
+	RecvPropBool( RECVINFO( m_bForceNoInterpolate ) ),
 
 	RecvPropVector( RECVINFO_NAME( m_vecNetworkOrigin, m_vecOrigin ) ),
 #if PREDICTION_ERROR_CHECK_LEVEL > 1 

src/game/client/c_baseentity.h

@@ -1287,8 +1287,6 @@ public:
 	// Entity flags that are only for the client (ENTCLIENTFLAG_ defines).
 	unsigned short					m_EntClientFlags;
 
-	bool							m_bForceNoInterpolate;
-
 	CNetworkColor32( m_clrRender );
 
 private:
@@ -1309,6 +1307,8 @@ public:
 	byte							m_ubInterpolationFrame;
 	byte							m_ubOldInterpolationFrame;
 
+	bool							m_bForceNoInterpolate; 
+
 private:
 	// Effects to apply
 	unsigned char 					m_nRenderMode;

src/game/client/cdll_bounded_cvars.cpp

@@ -99,7 +99,7 @@ class CBoundedCvar_Interp : public ConVar_ServerBounded
 public:
 	CBoundedCvar_Interp() :
 	  ConVar_ServerBounded( "cl_interp", 
-		  "0.1", 
+		  "0.025", 
 		  FCVAR_USERINFO | FCVAR_NOT_CONNECTED, 
 		  "Sets the interpolation amount (bounded on low side by server interp ratio settings).", true, 0.0f, true, 0.5f )
 	  {

src/game/server/baseentity.cpp

@@ -269,6 +269,7 @@ IMPLEMENT_SERVERCLASS_ST_NOBASE( CBaseEntity, DT_BaseEntity )
 #endif
 
 	SendPropInt		(SENDINFO( m_ubInterpolationFrame ), NOINTERP_PARITY_MAX_BITS, SPROP_UNSIGNED ),
+	SendPropBool		(SENDINFO( m_bForceNoInterpolate )),
 	SendPropModelIndex(SENDINFO(m_nModelIndex)),
 	SendPropDataTable( SENDINFO_DT( m_Collision ), &REFERENCE_SEND_TABLE(DT_CollisionProperty) ),
 	SendPropInt		(SENDINFO(m_nRenderFX),		8, SPROP_UNSIGNED ),

src/game/server/baseentity.h

@@ -814,6 +814,9 @@ public:
 
 	CNetworkVar( int, m_ubInterpolationFrame );
 
+	CNetworkVar( bool, m_bForceNoInterpolate );
+
+
 	int				m_nLastThinkTick;
 
 #if !defined( NO_ENTITY_PREDICTION )

src/game/server/player.cpp

@@ -594,7 +594,7 @@ CBasePlayer::CBasePlayer( )
 	m_hZoomOwner = NULL;
 
 	m_nUpdateRate = 20;  // cl_updaterate defualt
-	m_fLerpTime = 0.1f; // cl_interp default
+	m_fLerpTime = 0.025f; // cl_interp default
 	m_bPredictWeapons = true;
 	m_bLagCompensation = false;
 	m_flLaggedMovementValue = 1.0f;

src/game/shared/hl2mp/weapon_physcannon.cpp

@@ -550,6 +550,7 @@ void CGrabController::AttachEntity( CBasePlayer *pPlayer, CBaseEntity *pEntity,
 		pList[i]->SetDamping( NULL, &damping );
 	}
 	
+
 	// Give extra mass to the phys object we're actually picking up
 	pPhys->SetMass( REDUCED_CARRY_MASS );
 	pPhys->EnableDrag( false );
@@ -576,6 +577,8 @@ void CGrabController::AttachEntity( CBasePlayer *pPlayer, CBaseEntity *pEntity,
 	{
 		m_bHasPreferredCarryAngles = false;
 	}
+
+	pEntity->m_bForceNoInterpolate = true;
 #else
 	//pEntity->SetPredictable(false);
 	m_bHasPreferredCarryAngles = false;
@@ -633,9 +636,10 @@ void CGrabController::DetachEntity( bool bClearVelocity )
 		}
 	}
 
-#ifdef CLIENT_DLL
+#ifndef CLIENT_DLL
 	//pEntity->SetPredictable(true);
-	//pEntity->m_bForceNoInterpolate = false;
+	if(pEntity)
+		pEntity->m_bForceNoInterpolate = false;
 #endif
 
 	m_attachedEntity = NULL;
@@ -2534,11 +2538,11 @@ void CWeaponPhysCannon::ItemPreFrame()
 
 	//if ( localplayer && !localplayer->IsObserver() )
 	//	ManagePredictedObject();
-	if(m_hAttachedObject)
-		m_hAttachedObject.Get()->m_bForceNoInterpolate = true;
-	else
-		if(m_hOldAttachedObject)
-			m_hOldAttachedObject.Get()->m_bForceNoInterpolate = false;
+	//if(m_hAttachedObject)
+	//	m_hAttachedObject.Get()->m_bForceNoInterpolate = true;
+	//else
+	//	if(m_hOldAttachedObject)
+	//		m_hOldAttachedObject.Get()->m_bForceNoInterpolate = false;
 #endif
 
 	// Update the object if the weapon is switched on.